Cool arena horde mode shooter.
The Drones and Mech models look really nice and i like how you made the enemies react to shots by having them sway all around the place since they are flying. The Lasergun / Minigun combo of the Obliterator is also pretty fun to use.
Too bad you didn't have time to add sounds or music cause this would add a bit more to the game's atmosphere, but regardless doesn't detract from the solid gameplay, the only real issue i had was a bit of a performance drop once i reached wave 10 and upwards, and probably was due to the number of enemies present in the arena, cause once i managed to destroy a few, framerate went back to normal.
Other than that it's real fun to play, well done :)