Is this joke good enough? I don't think so. Maybe you do, but come on. It's a pretty boring, somewhat obvious subversion of a genre. You could just as easily have gone for Frankenstein (the monster) getting the normal brain instead of the messed-up one, and being an ordinary person. Or a radioactive spider who is released into the world, but is then crushed by someone's foot before he can bite anyone. I feel like I've heard these jokes in tons of different places. [update: Apparently I was getting Frankenstein confused with the Mel Brooks' parody Young Frankenstein, which, while it means that I've referred to two generations of Brookses in this post, also is a dumb mistake. so here's a new example: Man gets turned into werewolf, but it's always really cloudy out and so he can't tell if the moon is out or not.]
One such place, as Tomical pointed out in the comments, is a recent Saturday Morning Breakfast Cereal (recent here meaning last 6 months), which has the exact same joke (zombie movie is really romantic comedy). This is hardly the first time xkcd has copied SMBC, and I'm sure it's hardly the first time that some xkcd defenders will try to explain how it is a totally different joke (xkcd is left to right, smbc was top down!) and hopefully we can all yell at them. STOP COPYING OTHER PEOPLE'S JOKES, IT IS EXTREMELY LAME.