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