Here is the full list of all 22 Monster Blast achievements.
Mission Completed
finish Rotary King
finish The Nest
finish Mister Tentacle
finish World 3
finish Slimy Wall
finish Puffy
finish the Explorer
reach experience level 20
finish World 2
finish Roller Star
finish Panzer Boy
finish Jerry Jumper
kill 4000 enemies
get 10 kills with the support tower
reach experience level 10
finish World 1
finish the Shield Master
kill 2000 enemies
eat 20 fruits
finish Bob The Blob
kill 1000 enemies