it's a cool idea, but i think you should either have less levels or introduce more new mechanics each level, because right now it gets a little repetitive after a while.

the boss fights were really cool and funny, though. i enjoyed the final boss a lot.

sound effects would really improve the experience also.

oh! and i like that you took the time to even add an endless mode too. very thoughtful!

The collision boxes are sometimes unpredictable. Sometimes I missed those grass pillars. I think it was because when you turn (from right to left) to air strafe, your collision box gets flipped too (I think). 

Once I got used to the controls, the game was fun.  What I found really funny was that you can land on top of the opossums to avoid combat with them (also get a free ride).