These are some impressive visuals. Everything glows and there are great particle effects. Additionally, what you did with the title screen was really cool. It's tough getting the ai to just play the game on its own (I've done something similar in a game before). Cool touch having that happen in the background.
There are a few things I'll give criticism on though. The game could've used some kind of explanation/tutorial. Additionally, spawn rates on enemies didn't ramp up at all. This means the game didn't have any sort of inevitability and could drag on. Finally, it was unclear what was going on with speed at first. A bit more of a gradual increase in speed as you lose health would've made the "less health is more speed" relation clearer.
I did like the mechanic of "less health is more speed". More speed at first is really helpful. However, as you take more damage, it becomes too much.
Good job with your game.