The perspective is all messed up at the back (the handle is at a crazy angle). I don't really like the design personally (looks like a very simplified version of the Robocop handgun), but you could develop it more I think. It needs to be less of a box with bits sticking out, and more of a collection of shapes. The bumf says it's modular, and can be fitted with different systems - make it look like that. Make the grip/trigger section the base of it, and then have the barrel assemblies as separate parts, that look like they can be taken off. That'll add a lot of detail, and reduce the "handle on a box" appearance it has now.
