Really nice game, with downsides
This is obviously the work of a self-conscious programmer with a good understanding of what pleases the eye. However...
I think all the minor aspects you've managed to work into the game mechanics, like slowing down while touching an enemy, being hit by your own fire, and being impeded in your movement capactity by certain weapon (I'm looking at you, shotgun) are all good things in a game lacking challenge and variety, but this is not the case. In fact, they all add more difficulty to an already uber-hard game, only manageable at wimp level by the average player.
This is a game that just screams for an upgrading system, even if it's one devoted only to the most basic gameplay matters: I'd suggest upgradable walking speed and special weapons spawn rate at the very least, and I'm just naming the most trivial and non-creative ones I can come up with at the moment.
Other than that, a really good game that only lacks a quality switching setting (how come?) for slower computers. But I don't guess anyone's gonna complain about that since the graphic style is so amazing.
Good job.
-Kenji-