Viscera Cleanup Detail is about cleaning. After a brutal fight with endless waves of enemies, you must really live a bloody mess after yourselves. That's where Space-Station Janitors come in to play with their mops, buckets of water and biohazard bins to clean the area for the next bloody fight.
Your goal as a janitor to search the whole area and clean any kind of a trace of a brutal fight. Body parts, med-kits, bloodbaths and others signs of a harsh battle with forces of evil. For bullets casings or flares you can use a broom to gather thing and then throw everything into the incinerator and burn all the evidence.
In this specific DLC, Shadow Warrior, janitors arrive on a very first mission of Shadow Warrior 2013. Lo Wang fought through demons and his opponents, slicing his katana in their bodies and tearing them apart. And now it is your job to take your mop, a bucket of water and funky music to clean the mess up.