Spring can generate large 3D maps that change as the battle goes on, trees that set on fire as you approach them, moving water with reflections, etc.
Spring has different camera modes that allow you to engage in land, air, and sea combat. The trajectory of all projectiles also respond to the laws of physics.
Spring includes a series of games that you can play on the Internet or a local network (as long as you install the program's server, called Lobby server). They are PURE, Gundman, Star Wars: Imperial Winter, Evolution, Kernel Panic, and Expand and Exterminate. It also includes a few mods for Annihilation, although you need the original game to access them.
Don't forget to check the mods verification option during the program installation, otherwise you won't be able to play any of the games.
For Windows XP and Vista. Requires at least a 1GHz CPU, 256 megabytes of RAM, and 64 megabytes of video memory.