You put the Crazy Frog song at the end? I have lost all respect for this game. Everyone hates the Crazy Frog. (you could have at least simply used the original Axxel F song)
I think on the run and jump section, the camera could be lowered a bit. On the falling blocks section, maybe make the goal to jump up the blocks to the top? The disco part was cool, but is too easy since you can just keep running around jumping and only get hit one or two times. I like the music :)
On 2 player mode if both players are the same faction you can't tell who is winning since both sides are the same colour (on the bar at the top). Maybe add a black line between them? Also, make an online multiplayer version! It rocks!
This is so glitchy..... half of the time my hotkey for injection doesn't work, and it takes me about three tries to pull up a hut when I've just cast cage =[
Bug on the hammerhead challenge -- whenever I corner an enemy it gets stuck behind dead robots and is out of range from my jackhammers... had to refresh and restart =[