Here is the full list of all 20 Adventures of Pip achievements. It takes around 6-8 hours to unlock all of the achievements on Windows.
Completed the game.
Rescued all the villagers in Queen DeRezzia's Castle.
Completed all levels with a PERFECT rating.
Defeated Queen DeRezzia in her Castle.
Rescued all the villagers in the Lava Labyrinth.
Defeated Lord Magmalith in Lava Labyrinth.
Rescued all the villagers in the Galena Caverns.
Defeated Cragken in the Galena Caverns.
Completed 50% of levels with a PERFECT rating.
Rescued all the villagers in the Maddening Marsh.
Defeated the Temple Heart in the Maddening Marsh.
Purchased all available Upgrades in the Weapon Shop.
Purchased all Heart Containers in the Item Shop.
Collected 11,240 pixels in total.
Purchased an Upgrade in the Weapon Shop.
Rescued all the villagers in the Scarab Forest.
Defeated the Queen Grub in the Scarab Forest.
Purchased an Item in the Item Shop.
Purchased a Heart Container in the Item Shop.
Rescued all villagers in a single level and received a PERFECT rating.