Here is the full list of all 21 Munchy Mammals achievements.
You got gold in every blue level!
You got gold in every red level!
You got gold in every purple level!
You got gold in every green level!
You got gold in every black level!
Win the level in options
Set screenshake to max
Undo 1000 times!
Spend 10 minutes in a level without making a move
Eat your own tail
1000 moves in one level
Turn 1 mammal into 2!
Beat 5 levels in a row without undo/restart
Try to eat a food, that you can't eat
Try to go into wrong hole
Undo everything back to the beginning (6+ undos)
Finish a level in less than 1 second
Spend over an hour in 1 level
Win a level with 1 move more than required for gold
Win every level in options
Why was 6 afraid of 7?