Interesting game
You got a 5/9
Downsides:
1. You randomly popped out of no where which was distracting and after awhile even annoying.
2. The balloons sped up too rapidly and then didn't seem to get any faster.
3. From what I saw it is lacking additional challenges and side tricks that could make it more fun.
4. The biggest difficulty was flight control. When you start to move it's tight and slow, but then it's fast, rapid, and even slides some which actually caught me off gaurd a few times. I'm not sure if you intended it to be that way, and I'm fine with it, but it might turn some other people off from the game.
5. It lacked stages and overall variance.
6. You can scroll off the bottom or top for a quick trip.
Upsides:
1. It had some difficulty.
2. The first time you popped out was actually kind of funny. You should make it an event sort of thing though.
3. The game is simple and easy to jump into.
4. I didn't need to rattle the spacebar like a machine gun to kill things like in similar games.
5. No noticeable glitches.
6. The graphics could have been better, but were passable and satisfactory.
7. It IS slightly addicting, so you've got a good start on something with this game.
Summary: Please review the controls, game progression, and extras that go along the game to try and improve and build off of the base for a better, more unique, and more entertaining game overall. Other than that, you're good to go.