I found this game to be pretty good. I will admit that it got frustrating. You didn't have much of a defense when the enemies kept on coming and coming. I think the graphics aren't bad. I would like it if you could move the ship around. It is nice to control something so big.
I was surprised at how many enemies came up. It just seemed sudden. I couldn't see many visual improvements with the actual upgrades. It was still pretty nice. That firing sound did get annoying after awhile.