Cool.
The gameplay concept is great, but I think there should be a bit more variation in the types of enemies or something, at LEAST in the music. The game kind of drones on and on and on and the same music is playing the whole time. I really did nearly fall asleep several times trying to get the medal in survival mode (and for some reason it DIDN'T give me the medal when I reached that score, and after all that time I just wasted, I'm VERY disinclined to try again).
So yeah, I had fun for a while, but maaan the game is a chore. It's mentally exhausting sitting there doing the same thing for literally up to 2 hours.
For the survival mode score, I'd recommend making the difficulty grow faster, but setting the score lower. That way it balances out and isn't boring.
Overall, I'd really like to see you make a sequel and add tons more ideas to this foundation you've created here. :)