A damn good shooter
I really liked playing this game a lot, but there were a few things that I felt took away from the overall awesomeness of the game. In particular, you really need to go find an editor or go back through and clean up the story. I get the feeling English isn't your first language, but a cleaned up story would have made this a lot more engaging.
I also felt like I should have been able to track what purchasing upgrades actually modified. I know sheilds gave me more hit points, but I could not tell whether attack increased my attack power at all, or how much upgrading energy did, if anything.
I guess it's a personal issue, but I felt like if you were going to have a small battlefield with enemies that bounced around, then making the collision damage so high was really unfair at times, especially fighting a lot of those fast enemies in chapter 4. I had to spend about half an hour farming points until I think I finally just got lucky and scrapped through.
The bosses were fun though, and the game struck a good balance between being frustratingly difficult (as arcade shooters should be), but still playable if the player has patience. Good stuff.