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