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