This was a really well put together little game! A really neat, polished game. I got to a score of around 60 once I knew how to refill my ammo, but I think that was just me being dumb maybe, or spamming shots too much. I really loved the charge mechanic, it felt different and really juicy.
I don't know that I liked the ammo count, but I'm crap at aiming so I like to just spam! So I'm probably not playing the game in its intended way ;)
The audio fits really well - unfortunately I can't rate you very highly on it because you didn't make it, but it was chosen well. Loved the CRT effect. Overall a really consistent, polished game and I think it'd do really well in an arcade!