Here is the full list of all 18 Catsby achievements.
own 4 hearts
own 5 hearts
own 6 hearts
collect 4 donuts
collect 8 donuts
collect 12 donuts
collect 4 tokens
collect 8 tokens
collect 12 tokens
collect 16 tokens
own 200 golds
own 500 golds
own 1000 golds
100% map exploration
beat Boss Skull
beat Boss Evil commander
beat Boss Wizard
beat Boss Ghost