Here is the full list of all 24 Omega Strike achievements.
Open all chests in one game
Buy a Grand Feast
Buy a Chicken Treat
Defeat Doctor Omega
Defeat OmegaBot-2000
Collect all Life Cubes in one game
Defeat the Garbage King
Defeat the Sky Commander
Defeat Garbage Disposal Unit X13
Defeat Colonel Gurtz
Defeat Overseer Brodus
Defeat the forest guardian
Find 10 Life Cubes
Defeat Drillmaster 5000
Open 10 chests
Defeat Commander Armstrong
Defeat Wrassler
Collect 100 coins
Buy a weapon upgrade
Defeat Dozer
Collect 50 coins
Open a chest
Find a Life Cube
Collect 10 coins