Here is the full list of all 24 Princess.Loot.Pixel.Again achievements. It takes around 20-25 hours to unlock all of the achievements on Windows.
Archer saves King
Make a party!
Mage saves King
Berserk saves King
Paladin saves King
Make four deals with the cat in one run
Rogue saves King
Collect 15 artifacts in one run
Collect 3000G in one run
Collect 46 artifacts
Press TAB in the main menu
Warrior saves King
Necromancer saves King
Find baby
Get Rank C
Get Rank S
Collect 23 artifacts
Explode the door
Candlevania!
Get Rank A
Get Rank B
Die for the first time
Find hidden place
Start main Quest