The Brick Engine is a fast and simple lo-fi gaming engine. The engine provides a comprehensive API, including dazzling visual features, song playback, and collision detection: everything you need to make games with quickness and ease. The engine provides a straightforward C API and has language bindings for Tcl and Pascal, with support for more languages on the way.
Blood Makes the Grass Grow Green (BMTG3) is a multi-player, side-scrolling, 1-dimensional strategy game that pits two people against each other in a duel over a stretch of land. Each player is positioned in a bunker at opposite ends of the map and tasked with deploying the right personnel and vehicles to capture FOBs (forward operating bases) and overrun your enemy's bunker. Currently there are 5 different units available. Timing, unit selection, and basic strategy are all necessary for success.
Bitfighter is a game that feels a little like Asteroids on steroids. It's a multiplayer space-based combat and strategy game, featuring customized ships, multiple game modes, cool retro graphics, and smooth network play. It also includes a full featured level editor, Lua scriptable bots, and other cool features. It has a very active development team, so the game keeps improving.