While not a terrible game, I wouldn't recommend it because frankly the current price of $10 is much too high and also as it is a classic arcade-style shooter, if that is what you feel like playing then I might suggest you go and play one of those instead that you could get for much less and that would not have some of the same issues.
What I liked:
-Classic arcade-style shooting
-Ability to upgrade ship in between battles
-Decent number of affordable upgrades for ship
-Shields can make your ship tolerate more punishment than some other similar shooters
What I did not like:
-No tutorial or explanation of item pickups
-No saving even between missions (play all at once or lose your score)
-Default controls unintuitive; controls could be remapped but some are hardcoded and these are not identified anywhere
-For example, Space = swap secondary weapon. You can map Space to something else, but it will then do both (annoying)
-Sounds were not well balanced, so voices were always too quiet in contrast with background music even after adjustments
-Level backgrounds did not feel very dynamic, more like a scrolling wallpaper than your ship actually flying through a zone.