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