Here is the full list of all 12 The Wratch's Den achievements.
Finish the game in easy mode
Finish the game in normal mode
Finish the game in hard mode
Finish the game in nightmare mode
Reach 1000 pts in expansion mode
Reach 3000 pts in expansion mode
Build 5x rooms
Build 9x rooms
build 8+ doors
build 8+ darts
build 8+ spikes
sacrifice up to 5 minions to the altar