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