Fun little timewaster! I don't think I've played a shoot-down-as-many-planes-as-you-can-with-one-shot game before, pretty neat and innovative idea, though there's potential for plenty of other varied upgrades, like how about: different ammunition types (magma, lasers, rapid-fire), additional ammo, size of projectile, maybe some kind of atmosphere interference (magnetism? EMP?), could have some combo scores too... it could be a bigger game! Also stumbled upon two bugs: sound dies down after a few minutes of gameplay, first sound effects, then music, and the 'Complete Overhaul' medal isn't unlocking. :/ Second one's pretty major, hope it can be fixed!
-cd-