Here is the full list of all 20 Dark Gates achievements.
Destory Dark Gates on normal difficulty
Destory Dark Gates on easy difficulty
Destory Dark Gates on hard difficulty
Kill the Unnamed
We want no trouble
Scare a monster
Gather 5000 in gold
Successfully bribe a monster
Successfully negotiate with a monster
Reset the game
Save a party layout for next time
All heroes are dead, game over
Party is dead
It's alive!
Upgrade a hero
Save Game
Kill one hero
Land a maximum damage hit
Land a critical hit
Read HowTo