Homebrew (video games)
Homebrew is a term for software produced by hobbyists for proprietary video game consoles, which are not intended to be user-programmable.
The official documentation for many video game consoles is often only available to licensed developers, and these systems may use storage formats that make distribution difficult, such as ROM cartridges or encrypted CD-ROMs. Many consoles also have hardware restrictions to prevent unauthorized development.
Targets for homebrew games are typically those which are no longer commercially relevant or produced and with simpler graphics and/or computational abilities, including the Atari 2600, Nintendo Entertainment System, Wii, Nintendo 3DS, Wii U, Genesis, Dreamcast, Game Boy Advance, PlayStation, and PlayStation 2. Development can use unofficial, community maintained toolchains or official development kits such as Net Yaroze, Linux for PlayStation 2, or Microsoft XNA.
Several groups within the homebrew community have created unofficial games and software for consoles, as well as circumventing the hardware and software restrictions imposed on them to allow for the use of homebrew.
Development
New games for older systems are typically developed using emulators. Development for newer systems usually involves actual hardware, given the lack of accurate emulators. However, efforts have been made to use actual console hardware for many older systems. Atari 2600 programmers may burn an EEPROM to plug into a custom cartridge board or use audio transfer via the Starpath Supercharger. Game Boy Advance developers have several ways to use GBA flash cartridges in this regard.First generation consoles
Odyssey
In 2009, Odball became the first game for the Magnavox Odyssey since 1973. It was produced by Robert Vinciguerra who has since written several other Odyssey games. On July 11, 2011, Dodgeball was published by Chris Read.Second generation consoles
Atari 2600
Channel F
A handful of games have been programmed for the Fairchild Channel F, the first console to use ROM cartridges. The first known release is Sean Riddle's clone of Lights Out which included instructions on how to modify the SABA#20 Chess game into a Multi-Cartridge. There is also a version of Tetris and in 2008 "Videocart 27: Pac-Man" became the first full production game for the system since it was discontinued.Third/fourth generation consoles
NES / Famicom
Several compilers are available for the Nintendo Entertainment System, but like the Atari 2600, most development is done in 6502 assembly language. One impediment to NES homebrew development is the relative difficulty involved with producing physical cartridges, although third-party flash carts do exist, making homebrew possible on original NES hardware.In April 2023 NESFab, a new programming language for the NES, was released. The programming language is based upon C# and C++ making the development of software for the system relatively fast and efficient. Its release consequently witnessed the increment of homebrew games for the NES, amongst them being Mosh-Lift by Morphcat Games and Ballooney by Nikusoft.
Several varieties of custom processors are used within NES cartridges to expand system capabilities; most are difficult to replicate except by scavenging old cartridges unless the mapper in question was commonly used and thus cloned a lot, as is the case with the MMC3, or is simply consisted of discrete logic. One of the unofficial games that uses the MMC5 chip is Street Fighter II: Nostalgic Edition, a port of Street Fighter II: The World Warrior to the NES by Parisoft.
While the original Famicom and its clones can play unlicensed games, the 10NES hardware lock-out mechanism of the original model NES complicates the production of physical cartridges. The 10NES chip can be permanently disabled by performing a minor change to the hardware. The redesigned NES lacks the 10NES chip.
Genesis / Mega Drive
The Sega Genesis has no physical lockout mechanism, making it easier to release software for the system.Several flash cartridges for the system have been produced, including the Everdrive and Mega Everdrive line of flash cartridges for the Sega Genesis developed by Ukrainian developer krikzz, as well as the MegaSD by TerraOnion.
Pier Solar and the Great Architects, Paprium, and a port of Teenage Queen are examples of games that were released as physical cartridges. Other games include Sacred Line Genesis, Coffee Crisis, and Frog Feast for the Genesis and Mighty Mighty Missile for the Sega CD.
The 2018 game Tanglewood was notable in that it was developed using original Sega Genesis development hardware.
TurboGrafx-16 / PC Engine
The TurboGrafx-16/PC Engine has a comparatively small homebrew scene. The first homebrew title was MindRec's Implode in 2002, a few years after the system's last official release. The title was released on CD-ROM. Two years later, MindRec released Meteor Blaster DX on CD-R. Their official word on the change of CD format was that they were unable to be pressed to CD-ROM proper due to the glass mastering software suddenly unable to handle the unorthodox style of CD structure that the system expects. Five years later, Aetherbyte Studios released Insanity, a Berzerk clone, on pressed CD-ROMs, quelling the notion of unpressable CDs. Aetherbyte later went on to prototype and produce a new HuCard design called "AbCARD", which was fully compatible with the console. Aetherbyte celebrated the 30th Anniversary of the PC Engine since its release in 1987.There is one C compiler for the console known as HuC, however it has not been officially updated since 2005. The MagicKit assembler is generally considered the de facto assembler for the console, and comes included with HuC. Additional libraries for HuC/MagicKit include Squirrel, a sound engine developed by Aetherbyte Studios, and the SGX/ACD library, developed by Tomatheous, that gives the developer easy access to the SuperGrafx video hardware as well as the Arcade Card.
The cc65 C compiler is compatible with the console, although there is no development library supported for it.
There are a few original TurboGrafx CD games being made such as FX Unit Yuki: The Henshin Engine and a port of Mysterious Song in 2012. In 2025, Special Ninja Squad's demo was released for the system, coming out on HuCard format.
SNES / Super Famicom
Bung Enterprises released the Game Doctor SF hardware series. It allows users to copy games and run new games on SNES hardware. ROMs can be converted into the Game Doctor SF format and put onto a 3 1/2" floppy. Games as large as twelve megabits can be put on floppy disks formatted to 1.6 megabytes. An alternative device is the Super Flash, by Tototek, which allows multiple games to be burned onto a flash memory chip in a cartridge. This allows games as large as 48 megabits. The system can also program compatibility with a C compiler. The language program interest growth from French fans, porting Konami’s Asterix beat ‘em up.The run and gun game Alisha's Adventure used original Super Famicom development hardware. WaterMelon's action role-playing game codenamed ProjectN is a brand-new homebrew game for the SNES that is currently in development. Dottie -dreads nought- has been released for the 2021 SNESdev Game Jam, among Supercooked in 2022.
Neo-Geo MVS, AES, and CD
The Neo-Geo Home Cart and Arcade Systems can be tough candidates for homebrew development. Neo-Geo AES and MVS cartridges have two separate boards: one for video, and one for sound. If programming a cartridge for the system were to occur, it would involve replacing the old ROM chips with one's newly programmed ones as the cartridges are in a sense, Arcade boards. NGDevTeam, who have released Fast Striker and Gunlord, simply printed out their own board and soldered their own ROM chips onto it; this, however, can cause the Universe Bios logo to look corrupted if a custom BIOS were to be programmed. Programming for the Neo-Geo CD, however, is easier than programming for cartridges. The CDs themselves can actually contain both sound and video respectively. Depending on the Megabit count for a game program, load times will vary. A CD game with low Megabit counts will load only one time, whereas a CD game with higher megabit counts could load in between scenes, or rounds. As of 2014, other full games have been scheduled for release in physical form, such as Neo Xyx.Razoola, programmer of the Neo-Geo Universe Bios, was working in January 23rd, 2019 on a "Skeleton Game Driver" that supports two players. This ROM is meant to remedy the corrupted Universe Bios Screens, as well as work with an unmodified/stock Neo-Geo MVS or AES.
Razion is an example of an original Neo Geo game ported over to modern consoles, in this case the Nintendo Switch.