Hm...interesting. But no cigar.
With the name of Graves 3, I was expecting something interesting. And this was. But on the other hand, it didn't have much originality running for it. Here are a couple of things you could improve.
1. Perhaps work more on your graphics skills. There are tons of tuts out there for various things that you could use to make things more pleasing.
2. Allow the player to cycle through weapons on the left hand as well? I don't know how to tell you how annoying it was to only cycle through the right hand.
3. Develop somewhat of a story. If this is going to be a game, there should be at least a vague summary of a story which covers the basics. Who, what, when, where, why, and how.
Overall though, it did keep my interested 'til the end. Good job, man.