Faceball 2000 is an FPS developed by Xanth Software F/X, released in the early 90s for multiple consoles and handhelds. It is an updated port of their 1987 game MIDI Maze for the Atari ST computer.
You control a "happy face" and your goal is to shoot other happy faces to get through the maze.
The Game Boy version was published by Bullet Proof Software in December 1991. It allows up to 4 players with the 4-Player Adapter Cable.
The SNES version was published by Bullet Proof Software in September 1992. It allows two players in split-screen.
The PC Engine CD version (renamed simply Faceball) was published by Riverhill Soft in November 1993, only in Japan. It allows two players in split-screen with a Multitap.
The Game Gear version was published by Riverhill Soft in December 1993, only in Japan. It allows two players with the Gear-to-Gear Cable.
The Virtual Boy version, to be titled NikoChan Battle in Japan, was cancelled in 1996. A prototype ROM was found and dumped in 2013. A fan-patched version, Faceball Remastered, was released later that year.
It was long rumored that the Game Boy version would allow up to 16 players (as MIDI Maze did) by daisy-chaining multiple 4-Player Adapter Cables. However, this seems to be untrue. According to the lead developer, the 16-player mode exists in the game, but it requires a special adapter that was supposed to be bundled with the game, but was never released.