Successfully complete first level

Pull the lever while playing as zombie at level 7

Turn on the screen at level 14 and get the error message

Smash zombie and yourself by one piston

Die more than 100 times

Get killed by sealing after a jump from springer

Die while you controlling an enemy

Kill the zombie at the up in level 7 before you will be controlling him

Solve a puzzle with prism

Get yourself to level 21

Defeat The Engineer

Defeat The Freezebot

Kill an enemy by throwing him in a hole

Fall from a big high and do not die