I feel a little harsh writing this. It is clear that you've put alot of time and effort into this game, but I personally think you've put TOO much effort into this. It's aestetically displeasing since there is so much information on the screen. It's basically sensory overload, it would benefit from being simplified in terms of backgrounds. Hell, after seeing the 'shop' screen I wanted to turn it off. There was just TOO much.
The music is fairly OK. Not to my taste but it suits the game well so I have no complaints.
The gameplay is stright forward. I do however urge you. REMOVE THE GIRLFRIEND. It makes it way too difficult to progress and there is no chance in hell that I'll finish the game because of that 'feature'.
In terms of the shopping and stuff, it's fairly well and there is a nice variety of weaponary and upgrades. I think it would have benefitted from being split apart so having less information on the screen at a time. I know I keep complaining about the ammount of visual information but it's like opening a book to have an enjoyable quick read and finding it's like 10,000 words long and filled with technical terms. Your first instinct is not to read it, but to put it down.
Overall, it is a good game, it works and there is alot too it. I just feel that you've put too much effort into it and made it more complicated than it needs to be.
Best of luck with everything and I type this review with respect intended.
~Karlos