Finished a normal level without using abilities, weapons or melee.
Finished a normal level in under 20 seconds.
Finished a normal level without being seen.
Played 20 levels without dying.
Defeated the spiderbot.
Defeated the centipede.
Defeated the hovertank.
Killed 1000 enemies.
Killed 8 enemies with a single explosion.
Killed 3 enemies with a single railgun bullet.
Stopped the Overseer 1.0.
Completed all special levels.
Upgraded a stat to level 100.
Unlocked all unlockables.