Here is the full list of all 18 Crab Dub achievements.
Kill one Octopus
Pop 100 bubbles
Beat the game!
Unlock the final boss!
First zone completed!
Second zone completed!
Jump 10 times on jellyfish
Use 10 hearts
Chop 100 ice cubes!
Destroy 10 apples
Destroy 10 missiles!
Inflate 10 kittens
Third zone completed!
Jump 100 times on a space donkey!
Activate the magic pill!
Start the game in space!
Start the game on the little duck!
Start game for the Crab!