When a robot kills a human, we erupt into a pleading mist of blood, meat particles and tears, which you can't really trade for anything. But when a robot dies, he explodes in a shower of money, which, during between-wave lulls, you can exchange at any Upgrade Station for weapon, item and ability upgrades.
Here at Mann Co., we take care of our mercs. After you’ve completed your first mission, you will get, free of charge, one Mann Co.-brand canteen. It's equippable in your action slot and filled to the damn brim with life-giving air. If air’s not your thing, these canteens can also be filled with a variety of power-ups at an Upgrade Station. All we ask for in return is your bravery, plus some of the money you might have found on the battlefield. Each canteen holds up to three single-use charges of the same type.
Upgrade Stations give you a wide range of tactical options to choose from. Below, we’ve included a by-no-means comprehensive list of just a few of the weapon, item and ability upgrades you’ll need to hold the line against the Metal Menace.