I remember trying to mop a spill at my feet once, and the game said "You mop yourself and implode," or "You clean yourself and the universe collapses," or some weird shit that made it sound like you swabbed your way out of existence. I thought it was funny, but I'm not sure if it still does that or not. I like those weird little messages, though. :D
As for the things like "bat cave" and "mall zombies" and zombie scientists "dropping acid," I think those might be a bit of a stretch as opposed to intentional jokes thrown in. Now, like, if the bat caves had a chance to spawn some old superhero costume pieces that for some reason resembled a bat and had really good armor, perhaps with a broken "batcar" or something, that'd be cool.