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