A neat entry, with a pretty good concept. Good job!

I enjoyed the upgrades and thought the super fast asteroids were scary. 

I really like the replayability which this game offers :)  

I really like the game principle, especially the upgrade and bounty mechanics, but what I am missing is some kind of goal to work towards. Maybe there should some kind of progression, so that one unlocks new levels once one gets far enough.

Also, I think it would be good to have some way to lower your bounty while you are in the level, as it gets really difficult when too many enemies appear.

Overall, a very enjoyable game!

this is really nice, nice work :)