Needs work
It's a good start but it still needs a lot of work. The only weapon worth using as of now is the rocket launcher, and since it only takes one shot with it to kill the enemy, and you get the ammo right back, theres no point of using the other guns. The enemy needs to move around to make it more challenging. It would also be nice if there was a way to sneak up on an enemy. I highly doubt if you were walking around a corner, suprising an enemy, he'd have an insintanious reaction like they do in this game.
The graphics, while good, could be spruced up. The soundtrack gets a little repetitive, and a few different tracks at every new level would help.
I suggest taking a look at other games of this genre that are rated very high, and see if you can improve on your game. Sorry for being so critical, just trying to help.