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