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