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