Here is the full list of all 26 Obludia achievements.
Fire 100 Shotgun Shells
Throw 50 dynamites.
Find 20 chest.
Slay 20 Devils.
Complete the game.
Complete World 5 – Space Ship
Destroy 50 Alien eggs
Save 10 princess.
Complete World 4 – Hell Gate
Complete World 3 – Frozen Island
Complete World 2 – Ancient Tower
Eat 20 Hamburger.
Slay 20 chickens.
Find the legendary golden monkey statue
Complete World 1 – Dungeon of Doom
Buy your first dog.
Slay 100 monsters with blade.
Slay your first enemy.
Die 50 times
Cast 50x Glacial Spike spell
Cast 50x Ring of Fire spell
Cast 50x Lightning Strike spell
Slay 30 Ghosts.
Use 10x Holy Cross.
Find 1000 Coins.
Complete the game on HARD mode.