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