I like the music but there are some problems that need solving, especially with readability.
It's too easy to find a spot with the third Titan and just shoot in straight lines to kill everything (standing on top of the overcharge in the top left corner is a good example). It's too easy to exploit when the player can't move and shoot at the same time. I was bored at about 38k points and ended up killing myself too easily by trying to move around. It would help to have WASD controls to move while shooting and to place things around the map to collect in order to score instead of just killing things. That way, the player is encouraged to move around.
As for readability:
- It's hard to tell if you're hitting the little guys when you're not staring straight at your laser. A particle and/or sound where you hit an enemy would help a lot.
- It's a cruel surprise when you're surrounded and you find out where the level ends. A small barrier would help a lot.