Adventures of Johnny Jetpack: Guide Johnny through his 3D world of platforms and lava to collect all the coins. (Open Source)
BurgerSpace: BurgerTime clone for Linux, Windows, Mac, or BeOS in which you are a chef and must collect ingredients to make burgers.
Ladder: A classic ASCII based arcade game similar to Donkey Kong. (Requires the Java runtime environment.)
Robot Battle: An evolving programming game that allows players to design and build intelligent robots using a simple scripting language.
Super Pooch: A scrolling platformer for Windows similar to Super Mario.
The Adventures of Jason: Java platformer in which one or more players jump around in a rectangular world, trying to catch stars and shoot each other. [Open Source, GPL]
The Adventures of Toekan: A platform game for Windows with five different enemies.
TurboLode: 3D derivation of the game 'Lode Runner' for Windows with a real time stereoscopic mode.
VideoToons: Multiplayer Java platformer. [Open Source, GPL]