Being on time to things
One of your "teammates" killed you
Killed many opponents with the telekinesis powerup
Shattered a lot of frozen enemies
Killed a lot of enemies with fire
Dodged a lot of boomerangs
Killed opponents while unarmed
Killed an opponent after dying
Regularly killed yourself with the explosive boomerang
Telefragged an opponent
Mastered the disguise powerup
Squished several opponents with moving blocks
Spent a lot of time hiding in the bushes