Here is the full list of all 27 BUTCHER achievements.
Complete the game on "Hard" difficulty.
Complete the game in 1.5 hour on at least HARD difficulty.
Die 200 times in total.
Complete the game on "Harder" difficulty.
Find all skulls.
Beat The Last City.
Find 30 skulls.
Maul 200 enemies to death with a sawspider.
Kill 10 enemies with a single railgun bullet.
Beat Volcano Research Station.
Unlock new difficulty mode.
Find 20 skulls.
Beat Jungle Outpost.
Beat Old Military Base.
Find 10 skulls.
Kill 1000 enemies.
Repeat a single level 10 times.
Make 200 enemies die horribly by burning alive.
Beat Ironworks Facility.
Complete the game on "The Hardest" difficulty.
Complete the game in 1 hour on at least HARD difficulty.
Impale 25 enemies on hook by kicking them.
Impale 50 enemies on hook by kicking them.
Complete the game in 45 minutes on at least HARD difficulty.
Upload your level pack to the Workshop.