How Streets of Rage 2 used the Mega Drive Hardware to Create an Iconic Soundtrack

Streets of Rage 2 – called Bare Knuckle 2 in Japan – is a scrolling beat ‘em up video game that was developed by Ancient and released for the SEGA Mega Drive/Genesis console in 1992. It featured 4 playable characters – Axel and Blaze who were in the first game, as well as 2 new additions Max and Skate. The game offered players a range of combination attacks that they could use with each character, and a new versus mode where players could test their skills against each other. They could use any one of the game’s 8 stages to fight each other in, with a range of weaponry scattered around the stage. Due to its 5 difficulty levels and ability for players to choose how many lives they started the game with, Streets of Rage 2 had a low barrier to entry while still offering a challenging experience to fans of the series. Yuzo Koshiro who composed the soundtrack for the original Streets of Rage game returned for the sequel, writing all of the game’s music and sound effects except for 3 tracks which were written by Motohiro Kawashima.

When discussing Streets of Rage 2, strafefox (2018) said that it was one of the first SEGA games to be put on a 16 megabit cartridge which was 4 times the size of the cartridge for the original game. This allowed for more detail in the game overall, as well as additional space for sound effects and music. According to Ayano Koshiro – the head designer at Ancient – they only had around half a year of development time which makes the technical achievements of the game all the more impressive.

The SEGA Mega Drive was released in 1988 in Japan, 1989 in North America and 1990 for Europe. It was unique for the time as it had two on-board processors – the 6800 and Z80. The Z80 handled audio and had a 4 MHz maximum clock speed while the 6800 was in charge of all other operations and was faster with a clock speed of 7.61 MHz. The 6800 was actually a 32-bit processor that took in a 16-bit bus while the Z80 was an 8-bit processor (Mitchell, R, 2016). This meant that if lots of operations were happening at once, the music and sound effects of the game would be unaffected by any strain on the core processor (Mitchell R, 2016). By isolating the sound operations, developers did not need to worry about sounds and music stuttering which created a smoother experience for players.

A 32-bit processor has significantly more computational power than an 8-bit one. This is because it can read data from larger data buses, allowing for more accurate floating point numbers to be used. By increasing the number of bits available for a processor to use, this improves the speed at which it can complete operations. To complete an operation an 8-bit processor will need more instructions than a 32-bit processor, as the size of the commands it can understand is smaller. This meant that the 6800 was significantly more powerful than the Z80 as it took less time for the processor to complete the same action (Bond, K, 2016, p. 489).

The Mega Drive’s capacitors around the headphone jack and YM2612 chip

The Mega Drive also had two ways to output sound – through the RF port for the TV, or a headphone jack on the front of the console. The RF port could only use mono sound, while the headphone jack was capable of stereo. Additionally, it had a volume slider on the front of the console, an unusual feature that gave players finer control over the console’s volume. A reason why they might have added this slider was the headphone jack, as there would have been no other way to change the sound levels. Consequently, the circuit board is covered in capacitors to allow for the audio to be amplified through the port.

For producing sounds, the console once again had 2 chips – the YM2612 and an SN76489A clone that was integrated into the Z80. This was because the console was designed to be backwards compatible and the SN76489A was the sound chip in the Master System – the Mega Drive’s predecessor. As a result, composers for the system had access to 6 Frequency Modulation (FM) channels and 4 Programmable Sound Generator (PSG) channels which they could use to create music and sound effects. Furthermore, the YM2612 had an integrated digital to analogue converter (DAC) along with stereo sound capabilities (Collins, 2008, p. 40) which allowed for audio panning techniques to be used.

Panning is a technique in sound design which, “creates the illusion of a sound source moving from one part of the soundstage to another.” (Trandafir, 2017). It works by playing audio channels louder in one ear than the other to make it sound as though the audio is coming from a particular side. This can be used to make it feel like sound sources are moving, by changing the levels of channels gradually. Both Koshiro and Kawashima took advantage of the Mega Drive’s ability to produce stereo sound and you can notice this in tracks like Alien Power, Expander and Go Straight where different channels move from left to right throughout the tracks, giving them a more dynamic feel.

FM is a way of representing sound by changing the frequency and shape of the wave, while keeping the amplitude (height) the same. The main waveforms used in FM synthesis are sine, square, saw-tooth and triangle. These each produce a different type of sound with sine waves having a softer sound and more jagged waves like saw-tooth and triangle producing harsher tones. These basic tones could then be edited further to create unique patterns.

The different waveforms that can be produced by FM

According to Koshiro (2014), “With the introduction of FM synthesis, various instruments, like string, wind and percussion instruments, could all be played on one FM chip.” Since composers for the Mega Drive had 6 of these channels to work with, they could layer different waves on top of each other to create more complex sounds than previously possible. In the first level of Streets of Rage 2, Koshiro only uses 5 of these channels, leaving one available for the game’s sound effects. One of the channels on the YM2612 could be used to play sounds that had been recorded prior. Koshiro used this channel to play samples of the kick and snare of a Roland TR-909 (strafefox, 2018) while using FM synthesis to copy the Roland TR-808 drum beats, because they were popular drum machines at the time and he wanted to create an authentic club feel.

“Programmable sound generators (PSGs) are sound chips designed for audio applications that generate sound based on the user’s input.” (Wolf, Mark J. P, 2012). They take in an oscillating wave signal that is tuned to a set MHz value and a series of commands which are then applied to the wave signal, modifying how it sounds.

The SN7648A has 8 registers – 4 for volume control, 3 for generating tones and 1 for creating noise. As it was from a previous generation of consoles, it took its instructions in 8-bits, rather than 16. It can take a clock signal of up to 4MHz and has “a range of 10 octaves” (SMSPower, 2005). This meant that Koshiro was able to add 3 additional sounds to his composition on top of the 5 FM channels he was using from the YM2612, giving him greater depth and complexity in his compositions.

When dealing with real components, they aren’t always perfect, resulting in distortion of waveforms. This was particularly noticeable with the Mega Drive as the SN76489A had problems with the wave decaying towards zero. Furthermore, the YM2612 would truncate its 14-bit output to 9 bits which meant that the sound had to be passed through other circuitry – making the waves distort further (MD, 2015). Due to the distortion of the sound, the Mega Drive had a unique feel, known as the ladder effect as it was the only console that can produce this particular noise (Yuzo Koshiro, 2019).

His knowledge of computer programming and components made Koshiro stand out from other composers at the time since it gave him greater control over what the game sounded like compared to someone who needed a programmer to translate their compositions. When speaking on this subject he said, “I was trying to program on the computer to create sounds. It was really important for me to create music drivers or sound drivers.” (Koshiro, 2017).

To create his music, Koshiro used a variation of Music Macro Language (MML) that he created himself, called Music Love.  MML was a programming language used to notate music using text which had many different variations as it was unique to the interpreter and chips it was being used with. Therefore, it made sense for Koshiro to create his own version suited to the hardware that he was using, especially since it gave him more flexibility in how he could program his sounds as he said in an interview “Since I made my own editor and driver, I could control everything about the chip down to the fine details.” (Koshiro, 2014). The main way he modified it was by changing the language from being based on BASIC to coding “more like Assembly” (Koshiro, 2005).

Before he started to make music for the Mega Drive, Koshiro used the NEC PC-8801 for all his work and he used a variant of MML based on NEC’s particular version of BASIC. Koshiro stated during an interview with Redbull that the PC-8801 and Mega Drive conveniently had, “almost the same FM synthesis chips” (Koshiro, 2017) making music production simpler for him as the sounds he was creating on his PC would be true to how they would sound on the Mega Drive.

When they weren’t working on the game, Koshiro and Kawashima would go to clubs in Tokyo to listen to the newest club music, particularly at places like Yellow (Koshiro, 2017). They would take these new sounds and try to bring them into the game’s music. They were heavily influenced by popular dance music of the time, particularly tracks that came from abroad as both techno and the Mega Drive were more popular in North America and Europe than in Japan. Koshiro even took a trip to LA around 1988, where he “constantly had MTV on at the hotel” and he bought records to take home to Japan with him. He wanted to update the sound of the Streets of Rage franchise, in the same way that club and house music was constantly changing and evolving (Koshiro, 2014).

Streets of Rage 2 is still an influential and popular game to this day, with fans of its music across the globe. Koshiro’s music was so key to the game that he was one of the first video game composers to have a major credit for his work. The way that it uses the hardware is particularly impressive when compared to other games for the console as they had a tendency to sound the same. This was due to composer’s over-reliance on GEMS (Genesis Editor for Music and Sound effects) and the built in library of samples. It was released in 1991, and used in hundreds of games for the console, as it allowed musicians to use the MIDI format that they were comfortable with, rather than needing to learn how to program.

Both Koshiro and Kawashima continued to be successful game composers and they went on their Diggin’ in the Carts world tour in 2017 where they exclusively played music from game soundtracks that they composed together. Streets of Rage 2 was an introduction to techno music to many young people, and the game was a successful sequel although Streets of Rage 3 was less well received. Streets of Rage 4 has recently been announced for a 2019 release, leaving fans excited and questioning whether Koshiro will be returning to the franchise, 25 years later to write one more soundtrack.

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Collins, K. (2008) Game Sound: An Introduction to the History, Theory, and Practice of Video Game Music and Sound Design.  Cambridge, MA: MIT Press.

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Statistical Data

For my next project, I would like to create a tower defence game, either for mobile or tablet. Initially, I was unsure of which platform to choose, due to the prevalence of successful games within this genre for both platforms. For example, the balloons franchise is popular for both devices, and is easy to play despite a small screen size. This is due to the player’s freedom over the camera, allowing them to span over the battlefield.

Another popular tower defence style game available on mobile is Plants versus Zombies 2. However, despite a well-designed UI, the game interface can be too small on mobile, making the game more comfortable to play on tablet. This is due to the fixed number of rows to each level, forcing the player to always be zoomed out a specific amount. The ability to scroll across the map left to right mitigates some problems, but if the player had greater control over the camera, there would be less issues with mis-clicks.

Due to the prevelance of concerns with being able to successfully navigate the screen for mobile tower defence games, I have decided to make my game for tablet, to allow for more elements to be visible to the player without making the screen crowded.

To find some statistical data to support creating a tower defence game for tablet, I looked on statista. Firstly, I wanted to see how popular tower defence and other strategy-based games were. This information could give me an estimate for the reach of tower defence games and how well received they are by the mobile user base.

I found this graph particularly interesting, as it places strategy or tactical games as the most popular free-to-play genre in 2014 in France. I couldn’t find as specific information for the UK market, however I believe that it is important to consider the popularity of genres in other countries. If I wanted to have my game translated in the future, the french market would be highly considered due to the high potential for the game to be popular with a large portion of the player-base.


The next graph that I found was about past and future revenue for different game genres on mobile. Interestingly, strategy games made the most money in 2016, and they are projected to almost double in revenue in 2023. This shows that strategy and brain games are profitable to make, which could be useful in the future if I decided to release the game.

This graph shows the popularity of different mobile game genres in the UK. Compared to France, strategy games are significantly less popular, only holding a 10% share of the market, although you could argue that this type of game is still popular among players. Furthermore, this data is for Android only, and it includes paid games. Finally, a game doesn’t have to appeal to the majority of the market to be successful, so long as it satisfies a niche.


Web Analytics – Event Tracking

Here’s a link to the project

To add event tracking into the Spider Chase game, I used Google Analytics – a free service that allows you to see user events in real-time before displaying more in-depth statistics after 24 hours have passed.

To use Google Analytics in your website, you must include this code generated by Google in the head of your HTML document:

It was surprisingly easy to enable Google analytics on my web-page, and the instructions from Google Analytics explaining how to do so were easy to follow. Whenever you want Google Analytics to track an event on your page, you must create a gtag that contains the information that you want to track. Each gtag is made from a category, action, label and value. I used the category to denote the game that was being tracked, so that if I used Google Analytics for any future projects hosted on the same page, it would be simple to differentiate between events being generated by different games.

The event action describes what the player was doing to trigger an event to be tracked. The four tracking calls that I put into this game were die, restart, start and win. Labels are used to describe any values that you are tracking, in this instance I wanted to know how many attempts a player had, and what their score was, therefore these were the labels I used. Finally, the value is used to return any specific data points you want to track, which analytics will automatically provide average values for from your data.

To make the creation of the gtags easier, I created a small wrapper function that took in the different pieces of data needed for the tracking call as parameters and used them to generate the gtag. I set the event category as there was only one game available on the web page. By creating a wrapper function, I also minimised the risk of human error creating invalid gtags, or sending values that were not the intended variables that I wished to track.

To generate some data for Google Analytics to process, I sent a link to my game to a group of friends to try out. After 24 hours, this table was available:

By adding together start and restart calls, I can determine how many times the game was played – 15. Out of these games, 9 were lost, 4 were won and 1 exited the page before the game ended. However, if you compare this table to the Event Flow graph below, it shows that two people actually exited the game before finishing their attempt.

This shows that when looking at statistics, it is important to examine data in different formats, to minimise the risk of false assumptions. Interestingly, there is a similar exit rate regardless of if the player died or won the game, furthermore, no one successfully beat the game on their first try. There was one player who continued to play the game several times, before giving up without finishing their last attempt.

If I were to add to this project, I would want to create additional tracking calls at the end of the player’s run giving their x position, as this may indicate how far through the level the player managed to get before being caught by the spider. This information could be used to determine if there is one stumbling block that all players fall at, or if the level is uniformly difficult.

Introduction To Web Analytics

What Is Web Analytics?

Web analytics is a way to track how a web page is traversed and used by the people that visit it. According to Margaret Rouse, “The use of web analytics is said to enable a business to attract more visitors, retain or attract new customers for goods or services, or to increase the dollar volume each customer spends.”

Uses of Web Analytics

Web analytics is a powerful tool that can provide a variety of interesting data to web developers. The main method of identifying a single visit to a website is using a session. When the website is first accessed, a session is generated for the user. The session tracks the order in which pages are visited, where the webpage was accessed from in the world, how long the user visits the website for and where the user exits the webpage from.

Information on where your users are in the world is helpful as you can use it to guide future development such as localised versions or translations of your website. The exit page of the user (where they “bounce” from) is great for flagging whether certain pages are fulfilling users needs, or not providing the answers they want. If someone bounced from the “Contact Us” page, then you can be assured that they are more likely to have found what they were looking for. On the other hand, if the user bounces from a blog post on different types of rocks, maybe the page is simply not engaging to your audience.

Advantages of Web Analytics

Web analytics gives the developers key insights into how the users are interacting with and navigating their website. This leads to better informed development decisions, and minimises time wasted on features that no one is going to use. As web analytics is a quantitative type of data collection, this means you can use statistical analysis techniques to create summaries of your data.

How Web Analytics Can Be Used In Games

Web analytics can be applied to games through the use of event tracking. Events are triggered by the player performing a specific action, such as picking up a power-up, or completing a level. This allows developers to see where the player is getting stuck, what items they are missing and when in the game the player considers purchasing a micro-transaction. Tracking player interest in micro-transactions can be particularly important due to the money involved. Often it is used to optimise the options available to players, as it can show which bundles sell the best, and how likely a player is to make a repeat purchase.

Disadvantages of Web Analytics

In the world of social and mobile gaming, analytics are used heavily to influence game design. As a result, there are many copycat games that are difficult to tell apart from one another. Furthermore, web analytics only give you symptoms of design flaws with your game. As a developer, you may not understand why everyone is quitting after level three, unless you actually talk to someone playing the game. It may turn out that the game is extremely difficult at that point, or it is too easy and players are bored.


To use web analytics effectively, you need to combine it with other forms of data analysis, particularly qualitative methods to better explain what your event tracking is showing. Web analytics is a powerful tool for collecting huge amounts of data on what your players are doing, but it’s important to make sure that the data you gather is relevant, and can be used to improve your games in the future.

References: [website] [accessed: 13/12/2018]

They Are Billions and The 13 Basic Principles of Gameplay Design

They Are Billions is a strategy game where you must survive the zombie apocalypse and build up defences to protect your fledgling city. However, at the end of the match, an enormous horde of zombies will rush to your city, doing whatever they can to destroy it.

The 13 Basic Principles of Gameplay Design were created by Matt Allmer in 2009 based on the 12 Principles of Animation that he had learnt about at college. I will be using these as a framework to analyse They Are Billions.



Focal Point

The focal point of the game is defending your Command Centre from attack by the zombies. To do so effectively, players must build up their colony in size and resources. The expansion of the colony is a secondary objective in the game while defending your colony is the main focus of your activities. To unlock new defensive structures and troops, players must gather resources, while building research facilities and troop recruitment methods.


Each time you play the game, you choose how many days a particular run should last. Each run can last between eighty and one hundred and fifty days. At the end of this period of time, the final horde will attack. Throughout the entire course of the game, the player is anticipating the all-out-assault from the zombies at the end, shaping the way the player builds their colony and which troops they train.

Another way they are billions uses anticipation is by having each troop have two stances. One is on standby/navigating the map while the other is primed to attack. This way, the player can tell when their troops are ready to immediately attack, and when they are waiting to be told to attack or are in the midst of following a move or patrol order.

Announce Change

The map is filled with stray zombies which are attracted to human troops and structures by noise. Occasionally, they will wander towards your colony and attack. Separate from this, are zombie waves. These are announced to the player whenever there will be an attack along with what direction the attack will be from. The player is then given eight in-game hours to prepare their defences in the given direction before the horde makes its way through the map, picking up a few stray zombies along the way.



Believable Events and Behaviour

As you are exploring the map in They Are Billions, you will encounter zombie villages, old settlements that are overrun with zombies. These will continually spawn zombies to come and attack your colony, so it is key to take them out. Whenever you attack a building in a zombie town, more zombies will come flooding out of the building you are attacking and nearby ones to defend the town from attack. This forces the player to split their troops up and have some attack the buildings while others defend them.

This is an example of believable behaviour since when people’s homes or towns are under attack, they will attempt to defend themselves and others. Another way the game incorporates believable behaviour is when a colonist comes near to a zombie, they will run in any direction away from it screaming, as anyone would probably do.

Overlapping Events and Behaviour

Sometimes, smaller unannounced waves of zombies will attack your defences, at the points the game deems are the weakest. These are random, and come without warning from any direction, resulting in the player have to fight fire on multiple fronts.

When troops fight and kill zombies, their veteran percentage increases. Once it reaches 100% they upgrade, gaining higher damage, health and/or rate of fire stats. When playing the game, you can use this to your advantage by making death squads to run around killing zombies to become veterans or by posting new recruits on busy walls where zombies like to attack.

Sniper veteran and other stats


Since the game is in 2.5d, it doesn’t use basic physics such as gravity or drag. However, physics are implemented through the energy mechanic and the rate of fire of various troops and buildings. To expand your colony further, you must spread energy connections out beyond your base using Tesla towers. These bring more squares under your sphere of influence and are key to keeping all your defences running, as without energy any building defences shut down.

Another way energy is used is through shocking towers. These deal massive Area of Effect damage, but require a recharge time. This is cleverly shown through the coils around the top of the tower lighting up one after another. When the charge is fired sparks of energy shoot out of the tower. Other building defences also have delayed rate of fire and speed of missiles. For example, great ballistas have a medium rate of fire, but a slow travel time as they are giant mounted cross-bows. On the other hand, the upgraded versions of great ballistas – known as executors – have an extremely high rate of fire and fast travel time as they are automated gun towers.


Sound plays a vital role in They Are Billions to build the world around the player, to engage them in their surroundings and to create tension during critical events. Each of the 4 maps have their own environment sounds, to give each their own atmosphere. If you zoom into different aspects of the environment, each has their own sounds layered into the atmospheric noise. For example, if you zoom into a river or lake, the sound of running water is added to the background noise. I believe that Numantian Games spent a long time on the sound to ensure that the game felt fleshed out, and to help push across the steam punk setting of the game.

Whenever an action is completed for the colony, such as a troop is trained or a building is built, there is a short beep followed by an audio prompt of what has happened. This also occurs for attacks, and is useful for signalling events to the player when they may be focussing on something happening on the other side of the map. Without this feature, players may miss attacks, important buildings completions, and being able to organise their troops effectively.

Each type of building in the game has its own sound which is played when you click on it. This provides the player with information on what type of building they are interacting with, as well as giving the buildings life. For example, you can hear shouting from the Soldier’s Centre, laughter from the Inn and electricity zapping through Tesla Towers.

On top of each building having unique sounds, each zombie and troop type have their own voice lines, ranging from different pitched growls, to questions about when troops are going to be paid. This is the only time I feel the sound design could be detrimental to the game as the repeating voice lines from troops can become grating when you are fine-tuning their movement to route zombies a specific way. The troops voices still have use though, as when you select a group of troops, the most commonly selected troops voice line will play, giving the player a quick idea as to the make-up of the team especially if they check the icons displayed at the bottom of the screen.

Finally, the best way that They Are Billions uses sound is in the games music. Each piece in the soundtrack was recorded with the Bratislava Symphony Orchestra, giving the music a fullness which is often lost in games where digital instrument samples are used instead. The composer Nicolas Diteriks did an excellent job in creating a sense of looming danger and excitement through the music, and much of the game’s atmosphere and world-building would be lost without his booming score. The main theme is epic, using dissonance and rising chords through the brass section to create a feeling of impending doom before melting into softer strings to show hope that you may yet defeat the endless hordes. All the while, the percussionists hammer out a war beating, bringing a sense of the battle to come.

The build up to the end game is tense, with strings oscillating back and forth, trying to put your nerves on edge as you desperately prepare your final lines of defenses before the Final Swarm Theme crashes in. The way Diteriks used the brass to create scale and a sense of power gives me goosebumps whenever this theme begins. I have a personal passion for classical music, and seeing it utilised so effectively in an independent game shows how sound is crucial in creating a game that feels full of life.



They Are Billions has an interesting approach to pacing. As you can pause the game at any time, the player can take a breath and think about their next decision, in spite of their impending doom. When there are no zombies attacking, the game feels relaxed and slow, trying to lull you into a false sense of peace and security. As soon as zombies begin pounding at your defences, the game instantly feels faster. No matter the size of the zombies attack, every action you take has a sense of urgency, even if it is an unrelated building project on the other side of your colony. This is further added to through the games use of sound, and the way the brass section soars during an announced wave to inform you of the imminent danger.




As the game is in 2.5d, the developers have used a grid format to dictate where players can build, the sizes of objects, and to display areas from which buildings are taking resources from – this is key as buildings of the same type cannot draw resources from an overlapping area.

Walls are a key part of They Are Billions as they allow you to create layers of defences and minimize casualties when a zombie makes it past your outer-most defences; however there is a 2 layer limit to any wall that you build. If you attempt to build a wall 3 layers thick, the game blocks this action. I believe the game developers introduced this to prevent players from building incredibly thick walls to simply delay the zombies in one part of the map forever while they deal with an invasion elsewhere.

In They Are Billions, there are 4 possible maps, each with their individual terrain and challenges. Every map plays differently, and there are positives and negatives to each differing environment. By giving each map specific attributes, the developers can play around with the spacing of resources and obstacles to keep the game fresh as the player’s skill level increases. The maps are as follows:

  • The Dark Moorland – this map is unlocked at the start of the game, and has lots of terrain obstacles such as lakes, rivers and mesas which minimises free building space. While this can make organising your colony more challenging, it does allow for fantastic defence layering.
  • The Peaceful Lowlands – compared to The Dark Moorland, this map has a lot more building space, but is covered in sand making it difficult to build farms – a key food resource for many colonies. By changing the ground type in a lot of areas, the developers force the player to think strategically when building their colony.
  • The Frozen Highlands – the developers cleverly interpreted the theme of coldness in this map, by making all units move roughly 20% slower. This changes how easy it is for you to mobilise units to an area of you colony that is under attack and makes it feel like walls are infinitely further apart as you watch your troops trek through the snow and ice.
  • The Desolated Wasteland – the final map of the game is by far the most challenging. The map is overall open, but it has a larger number of Villages of Doom – a series of infected buildings that spit out zombies over time and must be removed before the end of the game to stand a chance at surviving. Furthermore, forest areas are few and far between, as well as green fields to build farms upon. Despite the openness of the map, it is difficult to build housing areas due to the prevalence of minerals such as iron or stone, which cannot be built upon.



Linear Design or Component Breakdown

This game has many different resources which you must balance alongside defending yourself from the oncoming zombie hordes. Each resource is interlinked with the others through the buildings, as to gather more of a resource, you need to use up your supply of a different resource. For example, stone quarries require wood to build, which need sawmills to collect that need gold for the workers. These workers need food, homes of their own, and said food and homes cost more supplies. Therefore, I believe the designers of the game used the component breakdown principle when creating They Are Billions. By identifying all the major sections of the game before starting to code it, Numantian Games ensured that all parts of the game would feel connected, and that no resource, building or battle would exist in a vacuum.




In They Are Billions you are the leader of possibly one of the last pockets of civilisation in the world, which gives context to the level of power you have over the colony and your ability to fine-tune every last detail down to the exact spot a troop will walk to. Players are able to make the game as hard as they like using the population and number of days settings before they start a new game. This affects their score modifier, which can range from 7% of their points to 440%. By giving players this level of fine control, the game developers ensure that despite creating a high skill game, even players less experience can give the game a go. More experience players often restrict themselves to create gameplay challenges such as only using the weakest class of troop, or not building one type of building that makes the end game easier.

The music in They Are Billions is critical in how the game makes the player feel, and their anticipation. So much of the game is built around the idea of the enemy are on there way and that it is inevitable that you will be attacked, that the frantic energy of the music is key in keeping the player engaged during tense sections of gameplay. It builds on the atmosphere for the player, and makes the world feel fully realised.


Communication is key in They Are Billions due to the way that priorities can quickly shift for the player due to a completed building, a random attack on your colony, or an impending zombie horde. When the player reaches a population goal, a pop up will appear to allow them to select a mayor, which is accompanied by a brief change in music and a voice alert along the lines of, “a colony needs a mayor!” To ensure that players are less likely to miss events happening across the map, alerts pop-up in the top left of the screen, as well as an announcement over what has occurred. If there are lots of alerts at once, only the first alerts voice line will play, and the rest will be notified to you using a beep. These announcements commonly include:

  • “Units under attack!”
  • “Attention: building completed.”
  • “Our defences are being attacked.”
  • “The infection is spreading across the colony.”

A lot of the game’s communication is done through sound, using announcements, changes to music and various sound effects like scraping on walls to signal to the player what is happening in the game. This was a good decision by the game designers, as when you have a large colony, you may be working on multiple projects at once, and visual alerts may not have been enough on their own for many key events.

The HUD on the bottom of the screen is where a lot of the gameplay takes place for the player. There you can see all your resources, the map, date, pause/play button and buildings you currently have researched. When you have the build menu open, anything that you currently do not have the resources for is greyed out, to indicate that it is currently unavailable for building. Also, when you have completed the research for some buildings, there are often holes left in rows of buildings, showing that there are more buildings to be unlocked through advanced research tiers.


The main appeal of They Are Billions is its unique take on the Real Time Strategy (RTS) formula by creating a crushingly difficult zombie game. They Are Billions has a target audience of experienced gamers, if you are new to the RTS genre, this is not the game to start with. By making the game so that a single mistake is potentially devastating or game-ending, the developers Numantian Games clearly aim the game at fans of this genre.

Another part of They Are Billions that makes it appealing to the player is that you play as the underdog against a far superior force throughout the game. When I play the game, I love taking out zombies with careful planning and strategy. This makes defeating the random waves and the end horde incredibly satisfying as you have beaten incredible odds.


They Are Billions cleverly utilises these principles of gameplay design to create a fun yet challenging game set in a cohesive universe. While some principles were possibly under-utilised such as physics, others were key in bringing the game together. The most important principles in the making of this game were sound, announcement of change, anticipation and communication. Without all four of these principles working together, players may have missed key events while playing that could affect their current plan and change they building strategy.



Allmer, M. (2009) The 13 Basic Principles of Gameplay Design. [website] [accessed

They Are Billions Wiki[website] [accessed 19/10/18]

Two Design Principles In Rogue Legacy

Core Gameplay Loops

A core gameplay loop consists of the player performing an action, the player’s reaction to what happens as a result and the need to repeat the initial action to progress.

Rogue Legacy is a Rogue-like game created by Cellar Door Games. It demonstrates this principle in the way that it utilises player character death. Whenever your character is killed, you are returned to the title screen, where you are prompted to “choose an heir”. They are the next character that you play with, and each has different attributes, which range from useful such as perfect memory to the ridiculous like alektorophobia (fear of chickens).

Once you have chosen your heir, you may then purchase upgrades, abilities and equipment that you can use for the rest of the game. If you never died, then you would be unable to upgrade your character, making further progression difficult.


Imperfect Information

Imperfect Information occurs when some part of a game is hidden from the player. This can range from locations to enemies and clues. Rogue Legacy utilises imperfect information throughout the game to keep it challenging.

As you explore the castle, you reveal rooms on the castle map. There is only one rule to the castle layout, the Maya is to the north, the Darkness below and the Gardens to the right. Otherwise, the player has no idea what room they are going to encounter next, or where they need to go to reach the next boss.

Another way Rogue Legacy implements imperfect information is through the character traits. Some characters are near or far-sighted, while others are insane and see enemies that aren’t actually there and cannot be defeated but do not cause damage. As a player, you can try to avoid characters that provide imperfect information, but there are occasions where it is a choice between how well you can see, and playing the run upside-down.


Despain, W. et al. (2012) 100 Principles of Game Design. San Francisco: New Riders.