Could stand a few improvements.
graphically, your game is excellent. The enemy design was enjoyable, and was frankly the only real drive i had to go as far as i did.
the game, otherwise... was rather... dull. I say this in the nicest way possible. ^_^; I mean, at its core, it was a good game, but thats all it was: the core of a good game. I mean, leveling up is rather pointless (you get stronger, but the enemies get stronger, so... what changed?) and the few upgrades only added a few nice sprinkles to the gameplay.
this kind of game has been done before, but with much more customization, enemies, and level variation. I think you tried to seperate yourself from the pack with the art, but it takes more than that to make a fun game: sure, its nice to look at, but that wont distract you from the same repeitiitve gamplay.
My advice is to make leveling up more meaningful, more than just a new enemy to shoot. Also, some variation in music would of been nice: its a cool song but it can grate on the nerves after a while. Additonally, customization options would be cool... and maybe a mini-game, or something, to break the repeptiveness?
All around, I'd say this is a solid game, but lacking in the origonality and in the gameplay: rocks are solid too, but you dont have a lot of fun just looking at em. X3
Thanks!