Here is the full list of all 28 Cursed Quest achievements.
Start the game
Kill a mob stealthily
Reach 20xp or more on a XP-Grave
Reach 40xp or more on a XP-Grave
Defeat the first boss
Lose your crossbow
Defeat the second boss
Defeat the third boss
Escape the spikes
Squash a blob
Reach 150 XP
Reach 300 XP
Defeat the fourth boss
Smash the coffin
Grab the mirror key
Defeat the final boss
Finish the game
Buy explosive arrows skill
Buy shockwave skill
Buy homing bullets skill
Find a secret room
Better than disneyland
Finish the game in cursed mode
Have 99 explosive arrows and 99 bullets
Buy all skills