BZFlag is a 3D, multiplayer, tank battle zone, capture the flag game that pits players against each other in a networked environment. It runs on Windows 95/98/NT/2000, Linux, MacOS 10.x, Irix, Solaris, and others. An OpenGL accelerator is highly recommended, but it is playable with 3D in software.
SuperTux is a side-scrolling platform game. The hero in this game is Tux the Penguin, the game's only reference to Linux. On the journey to rescue Penny, who has been kidnapped by evil Nolok, Tux faces 23 different kinds of bad guys while jumping and running through 101 beautifully-drawn levels. The soundtrack is available on last.fm and similar sites.
Critical Mass (Critter) is an SDL/OpenGL space shoot'em up game. Your world has been infested by an aggressive army of space critters. Overrun and unprepared, your government was unable to defend its precious resources. As a last effort to recapture some of the 'goodies', you have been placed into a tiny spacecraft and sent after them.
Take on the role of the Infernal Contractor and raise mayhem in this fast-moving 3D office simulation. This episode sees you racing round the office against the clock in an attempt to prove your fitness to the demanding recruiters. Slippery floors and dodgy ergonomics are all that stand between you and gainful employment. Hear encouraging phone calls from your agent, the harsh judgements of the recruiters, and the final countdown as you race for the finish line in this interactive simulation.
Kobo Deluxe is an enhanced version of Akira Higuchi's game XKobo. It adds sound, smoother animation, high resolution support, OpenGL acceleration (optional), an intuitive menu-driven user interface, joystick support, and other features. Kobo Deluxe uses SDL for graphics, sound, and input, which makes it possible to run the game on a very wide range of platforms.