Make backpack

Items bought and stashed in your backpack cannot be directly used by yourself; it can only be used by another player if they take it out of yours.

I feel this latter point should be made more explicit in the loadout/buy phase - Have a big message when picking what to buy, along the lines of “THIS PURCHASED ITEM WILL GO IN YOUR BACKPACK SLOT AND CANNOT BE USED BY YOU, ANOTHER PLAYER MUST USE IT”