Complete the indicated task to unlock the achievement.

Achievement	How to unlock
Centipede	Defeat the centipede.
Explosive	Kill 8 enemies with a single explosive.
Grit	Play 20 levels without dying.
Hard Work	Kill 1000 enemies.
Hovertank	Defeat the hovertank.
Overseer	Stop the Overseer 1.0.
Pacifist	Finish a normal level without using abilities, weapons or melee.
Runner	Finish a normal level in under 20 seconds.
Sneaky	Finish a normal level without being seen.
Spiderbot	Defeat the spiderbot.
Stat Master	Upgrade a stat to level 100.
Unlocker	Unlock all unlockables.
You're Special	Complete all special levels.
You've Just Been Erased	Kill 3 enemies with a single railgun bullet.