Finish a normal level without using abilities, weapons or melee.
Finish a normal level in under 20 seconds.
Finish a normal level without being seen.
Play 20 levels without dying.
Defeat the spiderbot.
Defeat the centipede.
Defeat the hovertank.
Kill 1000 enemies.
Kill 8 enemies with a single explosion.
Kill 3 enemies with a single railgun bullet.
Stop the Overseer 1.0.
Complete all special levels.
Upgrade a stat to level 100.
Unlock all unlockables.