Author: Ramon Santamaria @Raysan5

Edits: Rudy Faile @rudyfaile

Original Text | Posted here with Author’s permission.


A couple of weeks ago I played (and finished) A Plague Tale, a game by Asobo Studio. I was really captivated by the game, not only by the beautiful graphics but also by the story and the locations in the game. I decided to investigate a bit about the game and I was surprised to see it was developed with a custom engine by a relatively small studio. I know there are lots of companies using custom engines but it’s very difficult to find a detailed market study with that kind of information curated and updated. So I decided to write this article.

Nowadays a lot of companies choose engines like Unreal or Unity for their games (or rather, that’s what people think) because developing a custom AAA level engine requires lots of resources. I decided to list here some of the most popular custom engines with the team-sizes and notable titles released with those engines.

Most of the engines listed here have been developed along the years with multiple iterations and multiple video games, those engines have gone through multiple versions or even complete (or semi-complete) rewrites from scratch, with an engine name change. Also, important to note, most of those engines use multiple middle-ware for specific functionalities (Platform, Physics, Network, Vegetation, UI, Rendering, Audio…).

*Author’s Note: I tried to be as much accurate as possible with the information about the employees count (I checked the companies websites, Wikipedia or even the company LinkedIn) but take it with a grain of salt (some employees numbers could not be up to date).

The BIG Companies

*From left to right: Assassin’s Creed Odyssey, Final Fantasy XV, Red Dead Redemption 2

The below list is for very large companies, sometimes with complex corporate structures comprising multiple divisions (not only focused on video games) and multiple studios/subsidiaries also developing games. Some of them work with multiple engines, not only custom ones but also licensed ones.

CompanyEmployeesStudiosEngine(s)Notable Games
Activision/Blizzard~9200~9custom engine(s)Call of Duty series, Overwatch, Starcraft II, World of Warcraft
Electronic Arts~9300~36Frostbite 3Star Wars Battlefront II, Anthem, Battlefield 1/V, FIFA 20, Need for Speed series
Ubisoft~16000~54AnvilNext 2.0Assassin’s Creed series
UbiArt FrameworkRayman Legends, Child of Light, Valiant Hearts
SnowdropTom Clancy’s The Division 2, The Settlers
Capcom+2800~15MT FrameworkMonster Hunter: World
RE EngineResident Evil 7, Devil May Cry 5, RE2:Remake, RE3:Remake
Konami+10000~30Fox EnginePro Evolution Soccer series
Square Enix+4600~18Luminous StudioFinal Fantasy XV
Nintendo+6100~8custom engine(s)Zelda: BOTW, Mario Odyssey
Rockstar+2000~9RAGE engineGTA V, Red Dead Redemption 2
Epic+1000~11Unreal Engine 4Fortnite

The companies above invested in custom engines to have full control over the technology and also avoid the revenue cut imposed by licensed engines. Despite that fact, there are some big companies that in the latest years have chosen Unreal Engine for their productions, the most notable cases are:

  1. Capcom is using Unreal Engine for the new Street Fighter IV/V titles
  2. Bandai Namco latest big titles are using Unreal: Jump Force, Dragon Ball Fighter Z, Dragon Ball Z: Kakarot, Tales of Arise
  3. Square Enix also moved to Unreal Engine for several new titles: Dragon Quest XI, Kingdom Hearts III, Final Fantasy VII Remake

Interesting to see that those big three are Japaneses companies, maybe a market trend for that country? Also, maybe related (or maybe not), the Chinese holding Tencent owns 40% of Epic Games, I bet it has some influence in the Asian market.

Middle-size Studios

*From left to right: Rise of the Tomb Raider, Uncharted 4, A Plague Tale

Here we have the medium-small companies that decided to create custom technology for their titles.

The number of employees could be a nice reference to consider because a custom game engine is usually developed in-house (not outsourced) but note that some of those companies could have a big number of people because they also have in-house artist/audio teams while others outsource those parts of the development.

It would be really nice to know how many engineers are working on the engine division of each company, I’m sure there would be some big surprises for the different companies, probably in some cases by the low number of them!

Also, it would be interesting to have more info about the tooling included with those engines, it’s really difficult to have access to that kind of information. Engines tooling is usually a hidden-secret (beside some GDC presentation or some quick showcase video).

*From left to right: Horizon Zero Dawn, God of War, Death Stranding
CompanyEmployeesEngineNotable Games
Infinity Ward+500IW 7.0Call of Duty: Infinite Warfare
Bethesda~400Creation EngineSkyrim, Fallout 4, Fallout 76
Valve Corp.~360Source 2Dota 2, Half-Life: Alyx
Crystal Dynamics~350Foundation EngineRise/Shadow of the Tomb Raider
Naughty Dog+300Naughty Dog Game EngineUncharted series, Last of Us
Crytek~290CryEngine VThe Climb, Hunt:Showdown
From Software+280Dark Souls engineBloodborne, Dark Souls III, Sekiro
Remedy+250Northlight EngineQuantum Break, Control
Guerrilla Games+250DecimaKillzone Shadow Fall, Until Dawn, Horizon Zero Dawn
Platinum Games~250Platinum EngineNieR Automata, Bayonetta, Vanquish
Santa Monica Studio+200custom engineGod Of War series
id Software+200idTech 6/7Doom, Doom Eternal, Wolfenstein series
Sucker Punch+200custom engineInfamous Second Son, Ghost of Tsushima?
Insomniac Games~180Insomniac EngineRachet&Clank series, Marvel’s Spider-Man
Quantic Dreams~180custom engineDetroit: Become Human
Asobo Studio+140custom engineA Plague Tale
Mercury Steam~110custom engineSpacelords, Castlevania:Lords of Shadow series
Frozenbyte~100Storm3DTrine series, Shadowgrounds
Daedalic Entertainment~90Visionaire StudioThe Whispered World, Deponia series
Kojima Productions~80DecimaDeath Stranding
Media Molecule~80Bubblebath EngineDreams

Some observations from this list:

  1. Kojima Productions use Decima engine, developed by Guerrilla Games, despite not having a custom in-house engine, it’s surprisingly their accomplishments considering such a small team.
  2. Media Molecule latest game/engine (Dreams) seems to have been developed by only ~15 coders, amazing!
  3. Companies targeting one single platform, usually have less restrictions and can push the limits of that platform. Unfortunately, that’s a luxury that most companies can not afford.
  4. Asobo Studio, the company that originated this market study is not that small…

Small-size Studios (Indie Studios)

*From left to right: The Witness, No Man’s Sky, X-Morph Defense

Here we have some really small studios that also choose to develop a custom engine for their games. Note that most of those engines rely on other libraries/frameworks for certain parts of the game, the common choices we find are SDL (cross-platform graphics/input), OGRE (rendering engine), MonoGame (cross-platform game framework, also relyes on SDL, SharpDX, OpenTK, OpenAL-Soft…).

One question many people could ask is, what parts of the engine are actually coded by the developers? Well, it depends, but usually coders take care of the screen-manager, entities-manager and content-manager as well as the wrappers/interfaces to the other external libraries.

Second question, what parts of the engine usually rely on external libraries/middleware? It also depends on the company resources but usually audio-system, physics, rendering, networking, ui-system, terrain-system, vegetation-system and some other pieces.

*From left to right: Factorio, Thimbleweed Park, Owlboy

On the following list (and the next one below) I added the publishing date (only +2012) and the link to Steam for all the games… there are not many games with custom engine from small studios out there and I think they deserve to be recognized and supported.

CompanyEmployeesEngineNotable Games
Hello Games~25No Man’s Sky EngineNo Man’s Sky (2016)
Supergiant Games~20MonoGame-basedHades (2019), Pyre (2017), Transistor (2014)
Wube Software~20Allegro-basedFactorio (2019)
Ronimo Games~17RoniTech Engine (SDL)Awesomenauts (2017)
Runic Games~17OGRE-basedHob (2017), Tochlight II (2012)
Introversion Software~14SystemIV (SDL)Prison Architect (2015)
Exor Studios~14OGRE-based SchmetterlingThe Riftbreaker (2020), X-Morph: Defense (2017)
Tribute Games~11MonoGame-basedFlinthook (2017), Mercenary Kings (2014)
Thekla Inc. (Jonathan Blow)~10custom engineThe Witness (2016)
Terrible Toybox (Ron Gilbert)9custom engine (SDL)Thimbleweed Park (2017)
Matt Makes Games (Matt Thorson)~7MonoGame-basedCeleste (2018), TowerFall Ascension (2014)
Lo-fi Games (Chris Hunt)6OGRE-basedKenshi (2018)
D-Pad Studio6MonoGame-basedOwlboy (2016)
BitKid, Inc.6MonoGame-basedCHASM (2020)
Double Damage Games5OGRE-basedRebel Galaxy Outlaw (2019), Rebel Galaxy (2015)

Some observations from this list:

  1. Hello Games is a very small studio considering the size No Man’s Sky game and custom engine. Really impressive!
  2. Runic Games was dissolved in November 2017, the founders created Double Damage, not they are work on Echtra Games on Torchlight III.
  3. In most of those studios the people in charge of creating the game engine it’s only 1-3 persons!
  4. Lo-fi Games was a one-man team (Chris Hunt) for more than 6 years!
  5. Some of the games in this list took +5 years of development!
  6. Not many games… a couple of hits per year…

One-man custom engines

*From left to right: Stardew Valley, ScourgeBringer, Eagle Island

Finally, the list of the heroes.

Games developed by 1-2 people with custom game engines, engines mostly coded by one person! Respect.

*From left to right: Axiom Verge, Ghost 1.0, Remnants of Naezith

Creating an engine and a game from scratch to the point of publishing it is an extraordinary accomplishment, not many people in the world is ready for that. Almost all of them are 2D games, usually with very small budgets and developed along multiple years. Congratulations to the developers!

Company/DeveloperPeopleEngineNotable Game(s)
Lizardcube (Ben Fiquet and Omar Cornut)2?custom engine(s)Wonder Boy: The Dragon’s Trap (2017), Streets of Rage 4 (2020)
Pocketwatch Games (Andy Schatz)2?MonoGame-basedTooth and Tail (2017)
Justin Ma and Matthew Davis2custom engineFTL: Faster Than Light (2012)
Ed Key and David Kanaga2custom engineProteus (2013)
Flying Oak Games (Thomas Altenburger and Florian Hurtaut)2MonoGame-basedNeuro Voider (2016), ScourgeBringer(2020)
Terry Cavanagh1custom engineSuper Hexagon (2012)
Francisco Tellez1SDL-basedGhost 1.0 (2016), UnEpic (2014)
Grid Sage Games (Josh Ge)1SDL-basedCogmind (2017)
Luke Hodorowicz1custom engineBanished (2014)
Thomas Happ1MonoGame-basedAxiom Verge (2015)
James Silva1MonoGame-basedSalt and Sanctuary (2016)
Eric Barone1MonoGame-basedStardew Valley (2016)
Tolga Ay1SFML-basedRemnant of Naezith (2018)
Nick Gregory1MonoGame-basedEagle Island (2019)
bitBull Ltd. (James Closs)1MonoGame-basedJetboard Joust (2020)

Some observations from this list:

  1. Some of those teams are formed by 1-2 people but probably growed at some moment and/or outsourced some parts of the development (art, audio…). Usually the publisher also helps with some resources (localization, marketing…).
  2. Omar Cornut from Lizardcube is also the developer of Dear ImGui, a free and open-source immediate-mode gui library used by lots of AAA custom engines.
  3. Some of the games in this list took +5 years of development!
  4. Not many games… a couple of hits per year…

There are some other remarkable games using custom engines (usually XNA/MonoGame) that worth mentioning: Braid (2009), Super Meat Boy (2010), Terraria (2011), Dustforce (2012), Sword and Sorcery EP (2012), FEZ (2013), Dust: An Elysian Tail (2013), Rogue Legacy (2013).


I’ll start saying I’m biased, I’m really passionate about video games making technologies and I admire custom engines and game-making tools. I also contributed to custom engines ecosystem with my grain of salt: raylib and several game-making tools. I prefer a custom engine over a licensed one, it really feels extra amount of effort put into the product, usually translated into some specific mechanic of extra in-game details.

Said that, I must admit that creating a custom engine is a big endeavor and not many people are ready for that. I recognize Unity (and Unreal to less extend) have really democratized video game development, lots of small-medium size companies can use Unity today to quickly develop games and put them on the market, sometimes with very low budgets… But, still, lots of big companies prefer to rely on their own custom technologies.

From a game dev/teacher perspective I think students must learn how engines work internally with much detail as possible. Relying only on engines like Unity/Unreal for education to allow students develop eye-candy project in short-time is not the way to go. At the end of the day, someone has to write the engine and the tools!

Ramon Santamaria is a teacher and game developer from Barcelona, Spain and the author of Raylib, a simple and easy-to-use library to enjoy video game programming.