Quite an awesome game! Not very special but nice graphics and rather difficult even at Normal level.
Just a few small downsides...
* The victory/defeat screen responds to releasing the mouse button over the banner, which too often resulted in the sponsor window being opened (and switched to!) just because I was still holding the button trying to shoot at something. Not critical, but annoying.
* Some more details, and even numbers, could be useful for the upgrades. In particular, apparently "Resistance is Futile" and reduces damage by maybe 1 point per hit, which is useless when taking damage of 10 or 20.
* Due to this issue of some upgrades not being useful enough, I reset my upgrades at least twice during play. A useful feature of course, but perhaps it would be nice to also allow undoing the last upgrade or just upgrade and downgrade all items freely.
* How is this classified as a horizontal shooter? :)
On the whole, good job!