The weapons-gfx are awesome. Sadly I can't say the same for the Interface. The black should stay only for outline not for making details. And try to do some more difficult shading. Seriously pillow shading isn't much of a shading and something eye-candy. It makes me feel like all parts are roundish, bubbly...
I like the bullet of the MP3 it's kind of retro styled bulled from Duke Nukem or something.
I wish you good luck on finishing this.