There is a full instruction guide at crazy monkey.com. And for those of you that think this is just a bunch of survivals....thats probably why its called arena.
Here is the key in level 2:
1.Walk right ALONG THE GROUND until you reach a barrier.
2. Go back to the first tower on the left.
3. Climb up the tower until you see the 2ND platform on the the right.
4.Jump onto the platform and walk right (the key is a rotating grey rectangle with a red stripe).
5. TOUCH the door with the key to unlock it.
Also for those of you who are finding this game much to easy try completing the levels or fighting the bosses again. They will be much harder and additionally will give you weapons if you complete the level objective (see the objective by pressing "p"). Weapons can also be unlocked by getting high-scores in survival mode.
Note: The second set of objectives can only be accessed if you have beat the game already.
Have Fun!!
Thing Thing rules!! I love the jackhammer. However control for this game is a little low-quality. Also maybe you should have lowered the recoil just little bit.
I found that i got quite repetitive for the first couple of levels. You should make the game faster-pace so that its more fun. Also on easy your don't get gold for shooting things.
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