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