Full list of all 12 Orcs Must Die! achievements worth 200 gamerscore. It takes around 15-20 hours to unlock all of the achievements on Xbox 360.
Got 20 chandelier kills in one level
Completed Act 3
Killed 1,000 orcs
Completed Act 1
Completed Act 2
Won a level with 1 rift point left
Got 50 kills with explosive barrels on one level
Gibbed more than 200 enemies on one level
Kill 30,000 orcs
Complete the campaign on Nightmare mode
Earn 5 skulls on every level on War Mage difficulty
Get 50 kills with the rolling log in one level