It would be pretty awesome if after killing a boss you unlocked a new weapon that could give you an edge on another boss. Great game regardless and would love to see a sequel!
@Ta1nted
There is no bonus task, just beat every board and you should get it. Replay Mission 12 if it didn't show up. Once you beat it, it should take you to a new screen talking about more Creeper boards and stuff.
Anyone else have this problem: when you click on an enemy, to fight it, the combat menu never opens. I have tried several browsers, but it happens regardless.