Gel Gun Concept Art (Pffft)

This is some concept art for ~gizmolover, who has commissioned me for some concept art for one of the games he's making. Of course I'm happy to make anything, and especially during History class when we're watching movies, so today I whipped up whatever this is.
#5 is the main idea.
Notes:
The Gel gun, I figured, would be much like the portal gun. But that posed one problem: where would all the gel go? It shoots gel, a physical substance, not portals, which appear out of thin air. If this thing was to shoot gel, there would need to be a place to store the stuff. So... backpack gel generator! Basically there is a container to keep the gel (which is hooked up to the gun by the tube) and a processor-thing that creates the gel out of... stuff. Maybe water and space food-substance like thing. I dunno.
What else... Oh, it's not quite finished, the idea anyway. I want to come up with a more Portal-like design. Anything I seem to come up with at the moment is a bit retro-design, so I was trying to refer to the Portal gun and turret (seen on top) for help. It helped a bit. Ish.

Oh, and I'd put this in scraps, but y'know, I think it's better to show you guys how I go through ideas and what I'm doing right now. So... yeah. And this isn't scanned because I'm lazy. Also it's just concept sketches. So... yeah.

Tell me what you think, ~gizmolover.