The silver-lining with the wait for an updated version to download is I've since mastered completing the extremely buggy back-alley level that requires you to kill all enemies. Grenade the zombie standing on the first building to your starting left, shotgun the face-downers, assault rifle the dumpster-divers. Dogs are the primary mobile targets, since they can quickly overrun you. Pop them in the head a couple times with the pistol, then clean up the wandering riffraff. Save a few bullets for the stuck dog behind the metal railing on top of the building behind your starting position. Done.