A nice platformer, I only have two suggestions. It seems like the animation for the edges is a little off of where the edges actually are, and the "pumpkins collected" number needs to be in a smaller font, because right now it runs over.
I also played all the way up with all the upgrades, and my insight is this: I think that the upgrades are both too expensive and too powerful. I think it would probably play much better if the "can't take damage" and "no gauge" upgrades were removed entirely, and the others scaled down in cost, say double shot to 750 and rapid shot to like 1250. And then, put in an end to the game, say level 20 you storm the grey guys's castle, and when you get in there, you win.
Don't take that too harshly, I'm just a balance nut. In here is the core of a really good game.
for some reason it seems like the computer is infinitely better at melee than a human player, and I think that perhaps slower, more defined melee attacks would fix that problem.
 "Pumpkin Collector"){kind=icon}
 "Champion"){kind=icon}
 "GO!"){kind=icon}
 "KJB Billiards"){kind=icon}
 "Chaos Faction"){kind=icon}