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.
Press TAB in the main menu
Candlevania!
Find hidden place
Get Rank S
Find baby
Get Rank A
Die for the first time
Get Rank B
Start main Quest
Warrior saves King
Archer saves King
Mage saves King
Get Rank C
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
Explode the door
Collect 3000G in one run
Berserk saves King
Necromancer saves King