The objective of this game is to kill Grelok, for which there is no physical reward. In the Publishing wing of Hubris Comics, some terminals will allow you to play a text-based adventure (ala Zork: The Great Underground Empire) called Reign of Grelok (beta). Note: Updates / DLC may disable this! Try using body parts instead (but Fast Travel still won't work).
You can even fast travel with it - but when you appear at your destination the drum falls to the ground and you have to pick it all back up again. Fill up the drum by physically picking up items and dropping them in and you'll have an instant 'shopping cart' for all your stuff. First go through and clear an area of enemies, then grab (Click the right analog stick) a 55 gallon drum. If you are having trouble carrying with over-encumbrance, this cool trick could help you tote around some extra gear.