The game seems nice but there are a few issues that made my play session unenjoyful (does this word exist?).
Here are a couple of suggestions:
1. The flying bugs speed is too high, avoiding them is hard. (They are also too big, maybe changing either the size or the speed will do...)
2. The shooting things fire-rate is too high and the bullet speed too.
3. The camera is zoomed too close, it should allow the player to have a wider view. When you can see enemies they are too close and it's hard to react (their speed doesn't help)
I think that the more important is point 3, the camera should be placed much farther. I think that doubling the current view size should be fine, and will help playability dramatically.
Also I don't totally like the feel of the character's jump, but it's not a big issue.
Hope this comments will help in the development process. This is meant to be positive criticism.