Here is the full list of all 16 Caterpillarnoid achievements.
Open 50 ammo boxes!
Defeat the boss
Destroy 150 enemy's projectiles or bombs
Collect 100 coins
Open 25 chests
Complete all levels with ships
200 fireballs
Break 1 000 bricks
Gather some flowers
-1 sec of poison duration
-0.9 sec of freezing duration
Destroy 50 enemy's projectiles or bombs
Defeat 50 enemies
Don't give up!
Defeat the boss (hard/very hard)
Get 100 000 score