Homebrew, when applied to video games, refers to games produced by hobbyists for proprietary video game consoles which are not intended to be user-programmable. The official documentation 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 have hardware restrictions to prevent unauthorized development.
Development can use unofficial, community maintained toolchains or official development kits such as Net Yaroze, Linux for PlayStation 2, or Microsoft XNA. Targets for homebrew games are typically those which are no longer commercially relevant or produced, and with simpler graphics and/or computational abilities, such as the Atari 2600, Nintendo Entertainment System, Wii, Nintendo 3DS, Genesis, Dreamcast, Game Boy Advance, PlayStation, and PlayStation 2.
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. Efforts have been made to use actual console hardware for many older systems, though. 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 and 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. Several varieties of custom processors are used within NES cartridges to expand system capabilities; most are difficult to replicate except by scavenging old cartridges. One of the unofficial games that supports parallax scrolling and the MMC5 chip is Street Fighter II: Nostalgic Edition, which is a port of Street Fighter II: The World Warrior developed 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 (also known as the New-Style NES or the New Famicom) lacks the 10NES chip.
Genesis / Mega Drive
The Sega Genesis has no physical lockout mechanism (instead relying on software encoding), making it easier to release software for the system. 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.