Here is the full list of all 55 Cursed Gem achievements.
Complete the Tutorial
Try to avoid starting the adventure
Die for the first time (it wont be the last one!)
Complete Level 1
Complete Level 2
Complete Level 3
Complete Level 4
Complete Level 5
Complete Level 6
Complete Level 7
Complete Level 8
Complete Level 9
Get 100 gems on Level 1
Get 100 gems on Level 2
Get 100 gems on Level 3
Get 100 gems on Level 4
Get 100 gems on Level 5
Get 100 gems on Level 6
Get 100 gems on Level 7
Get 100 gems on Level 8
Get 100 gems on Level 9
Get 100 gems on Level 10
Get 100 gems on ALL levels
Complete Level 1 without dying
Complete Level 2 without dying
Complete Level 3 without dying
Complete Level 4 without dying
Complete Level 5 without dying
Complete Level 6 without dying
Complete Level 7 without dying
Complete Level 8 without dying
Complete Level 9 without dying
Complete level 1 without light
Complete level 2 without light
Complete level 3 without light
Complete level 4 without light
Complete level 6 without light
Complete level 7 without light
Complete level 8 without light
Complete level 9 without light
Complete all levels in Hardcore mode
Complete whole game without dying
Get killed 20 times from spikes
Get killed 20 times from fire
Get killed 20 times by blades
Get killed 100 times in the same level
Complete a level without getting any gems
Complete a level using the CRT shader
Use the soapstone for the first time
Reach the bottom of the broken bridge
Get all skins
Get all hearts
Scape with the biggest diamond
View the credits
Get all achievements