Here is the full list of all 14 Critter Crunch achievements.
Complete both Adventure mode and Puzzle mode
Win an online Versus match
Complete 35 Adventure levels while also feeding Smalls to completion
Complete Challenge mode
Survive to level 9 in Survival mode
Complete 25 Puzzle levels
Unlock Survival mode
Complete 6 Combos in a single level
Complete a puzzle level with moves remaining
Complete 10 Food Chains in a single level
Unlock Challenge mode
Pop a chain that is 15 critters long
Unlock Puzzle mode
Reach experience level 5 in online Versus mode