Reach 500 points without missing a single shot.
Kill 20 enemies in rapid succession.
Kill 30 enemies with a single shot from a railgun.
Detonate 30 bombs with a single shot.
Kill an enemy with a deflected bullet.
Kill 1000 asteroids.
Kill 1000 UFOs.
Have 50 asteroids in the level at the same time.
Reach 1000 points without moving.
Reach 2000 points in arcade mode.
Reach 4000 points in arcade mode.
Reach 6000 points in arcade mode.
Complete all challenges in a singleplayer mode.
Complete all challenges in coop mode.
Survive for 180 seconds.
Resurrect an ally in coop mode.