Just a minor suggestion here - I'm assuming that the secondary weapon slot fills with the same weapon as the primary slot to represent it taking up both hands. Would be nice, in this case, to display the secondary slot weapon at 50% transparency or similar, instead of it looking like your soldier is carrying two shotguns for instance. Another option would be to simply grey out the secondary slot unless a one-handed weapon or item is equipped in the primary slot.
EG.
- Equip Assault Rifle in Primary Slot
- Display Assault Rifle at 100% opacity in Primary
- Display Assault Rifle at 50% opacity in Secondary