Here is the full list of all 21 Slime Crunch achievements.
You crunched your first slime.
You beat level 1!
You beat level 2!
You beat level 3!
You got gibbed by a saw.
Slimes can fly, right?
You beat level 4!
You beat level 5!
You beat level 6!
You beat level 7!
You beat level 8!
You beat level 9!
You beat level 10!
You beat level 11!
You beat level 12!
You beat level 13!
You beat level 14!
You beat level 15!
You beat level 16!
You beat level 17!
You beat level 18!