This game seems pretty mixed overall for everything.
The audio seems both good and yet bad.
The good being the footsteps fit the pacing yet enemies do not seem to make noise from what I notice. The calm music on the starting screen is nice too. The sound of square bullets hitting foes reminds me of old retro video games too.
The bad being the music for the main level itself just seems really odd, at least to me it does.
The gameplay while I do see you did update it still seems a bit frustrating. Not going to give a low score mainly because I realize this is not exactly my type of game. It is fun if you can get the handle of things though.
The graphics are retro and remind me of some other older games I have played on Newgrounds over time. Simplicity in style is sometimes the best way to go when making a game. :)
Overall, seems mixed but it is not bad. Just seems to be a game that takes a little time to get used to.