0verkill is a client-server 2D deathmatch-like game in ASCII art. It supports free connecting/disconnecting during the game, and runs well on modem lines. Graphics are in 16-color ASCII art with elaborate hero animations. 0verkill features 4 different weapons, grenades, invisibility, and armor. The package also contains reaperbot clients, a simple graphics editor, and a level editor.
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.
BurgerSpace is a game in which you are a chef, and must walk over hamburger ingredients (buns, meat, and lettuce) to make them fall from floor to floor, until they end up on the plates at the bottom of the screen. It requires the SDL multimedia library. It is a clone of the 1982 BurgerTime video game by Bally Midway.
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.
Cosmosmash is a game where you control a base that must destroy rocks before they hit the ground, or you lose points. You must also prevent "spinners" from touching the ground, or your base will explode. This game is a clone of the 1981 Astrosmash video game for the Intellivision by Mattel Electronics.