Unlockable Bosses:
Unlock the following Bosses by performing the corresponding tasks:

Biker Ben – Defeat Biker Ben on Training Level 6.
Cavegirl Carmen – Defeat Cavegirl Carmen on Nature Park Mission 8.
Rabid Rabbit – Defeat Rabid Rabbit on Playground Mission 8.
Snorkel Jane – Defeat Snorkel Jane on Beach Mission 8.
Trooper Tim – Defeat Trooper Tim on Plaza Mission 8.