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