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