Not a gun expert (nor particularly fond of them), but I'll try and analyze most of them: PDW: Drum magazine, folding stock, gun rail and attached reflex sight Heavy shotgun: Side-mounted handle for right hander users, absolutely MASSIVE drum magazine (carrying more than one magazine must be a pain in the ass), muzzle break, and a reflex sight. Pump action shotgun: Bullpup design with a gunrail for attachments and a foregip. Assault rifle: Top: Curved magazine, gunrail with attached sights, foregrip and folding stock. Bottom: Silencer (or suppressor, can't tell), with a regular magazine, gunrail with different sights, foregrip, and a folding skeleton stock. Marksman rifle: Silencer with a gunrail and attached long-range scope. Semi-auto pistol: Nothing too special, other than an attached sight and silencer on the right.