This project is dead AFAIK so here is the best build.Here
is the most current build.What It's Got:
-SFXR sound effects.
-Levels, classes, etc loading from XML files.
-Level editor with incomplete support for props (see if you can guess the secret tree key).
-A special block to test ladders/monkey-bars.
-Actual ammo system.
-Some sort of message system.
-Throwable kits (that don't do anything).
-Super nice platforming and controls.
-Super buggy collisions between bullets and moving players and an unregulated timestep.
Bonus diagram of how jet combat could possibly work: