Nice concept, but it's got problems.
-Movement speed is way too fast. Holding the movement keys makes you almost instantly zip across the screen!
- Killing enemies feels very meh. An explosion animation or some sound effects would help a lot.
- The player needs invincibility frames after being hit. If there's a string of bullets coming towards you, then it's really easy to die instantly.
These are pretty simple things to fix and if you do I think you'll have a solid game. Nice effort all the same. I can certainly see what you were going for :)