Here is the full list of all 22 Heroes of Delum achievements.
Survive 15 minutes
Kill 5410 enemies
Save a hero
Save 54 heroes
Play with at least 1 player
Die while closing a rift
Win in normal
Win in hard
Win in hell
Win in impossible
Win 54 games
Win a game without building any elemental tower
Build your first tower
Build 54 towers
Build 1337 walls
Build 2 mines
Collect a chest
Collect 20 chests
Share a chest with at least 1 other player
Close a rift
Close 15 rifts
Close a rift with at least 1 other player