Experimental Atari Multiplayer Arcade
An experiment in using AI coding agents to modify vintage games. Claude Code changed five Atari 400/800 games from the early 1980s to support four players at the same time. They run here in an emulator, and up to four people can play each one together online.
Wizard of Wor 4-Player
Roklan's 1981 Atari 400/800 version, modified for four simultaneous players (yellow, blue, green and purple). The original supports two.
Pac-Man 4-Player
Atari's 1982 cartridge, modified so four Pac-Men share one maze at the same time; the original has players take turns. The modification also adds a speed boost and a VS mode.
Joust 4-Player
Atari's 1983 cartridge, modified for four knights at once, in free-for-all or team modes. The original supports two.
Demon Attack 4-Player
Imagic's 1982 cartridge, modified for four laser cannons at once against the same waves of demons. The original has one cannon; its two-player games take turns or share it.
Donkey Kong 4-Player
Atari's 1983 cartridge, modified so four Marios climb the same board at once: a race to Pauline. The original has one Mario; its two-player games take turns.
Seats
Each game has one room with four seats. If a seat is open when you arrive, you take it; otherwise you can watch and join a line. When a seat opens, the next person in line has 10 seconds to take it. Every game runs as a 4-player game, so an empty seat's player is still in play and can be taken over mid-game.
Controls
Arrow keys or WASD and Space, a gamepad, or the on-screen controls on a phone. Enter is START between games.
The emulator
The server runs an Atari 800 emulator, and every browser in the room runs an identical copy of it in lockstep; only joystick input travels over the network. These versions need the 400/800's four joystick ports.
Status
Experimental. The game modifications were written and tested by AI agents using automated emulator tests, and bugs are likely. Each room has a Report bug button.