This was a surprisingly good episode. Man-Bat is an awful villain, but here, somehow, they made him work. I think because they just totally ignored the whole "this is the flip side of Batman!" junk that was Man-Bat's original (terrible) purpose. Also because the whole thing had a real sense of tragedy about it, it actually felt somewhat emotionally resonant.
Kirk Langstrom had a real sense of desperation about him - it actually made me think of Lon Chaney Jr in The Wolf Man - he knew he had done something terrible, but he didn't know what, and there's something both terrifying and heartbreaking about that. The evocation of The Wolf Man in this episode is somewhat strange, given the fact that just two episodes ago there was an entire story about werewolves, and it didn't make me think about Lon Chaney Jr once, except maybe in a, "man, I wish I was watching The Wolf Man right now instead of this garbage" kind of way.
My one problem with the episode is that the twist actually makes no sense, given that we see the two Langstroms in bed, fully pajama-ed, seconds after we see Man-Bat. So what, when the Man-Bat was de-transforming it decided to change into its pajamas and gently get into bed? And then somehow completely forgot about this intermediary stage? But apart from that one logic-flaw, the episode was actually pretty good.