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