Killer work. I would say kevin's gun need the Nerf logo covered, And you can do some silver dry-brushing on his, followed by a very diluted brown wash to mute the silver. When I used to build model kits, I would take a larger brush (relatively speaking) and get some silver paint on it, (not much) brush it on cardboard until it was almost dry, then hit the high spots VERY lightly all over with quick strokes (heh). brings out the details, and the acrylic brown will create an uneven "grime" all over.
I'm digging this. Hope to see you on the Jumbo Tron at the Ralph!