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.
Berserk saves King
Archer saves King
Mage saves King
Paladin saves King
Rogue saves King
Make a party!
Make four deals with the cat in one run
Collect 15 artifacts in one run
Collect 3000G in one run
Collect 46 artifacts
Collect 23 artifacts
Necromancer saves King
Warrior saves King
Candlevania!
Find baby
Explode the door
Get Rank S
Get Rank C
Press TAB in the main menu
Get Rank A
Find hidden place
Die for the first time
Get Rank B
Start main Quest