I've mentioned before how much I love the parallel universe stories. The idea of the multiverse fascinates me. So this one shot should have been right up my alley, but it largely fell flat with me.
This story starts out with Mr. Mxyzptlk and Bat-Mite fighting in a silver age DC world. Their fight ends up destroying the whole universe to which they move on to Earth 2 and then so on and so on through various DC universes, destroying each one as they go. At the end they share a good laugh and with the blink of an eye all is restored. And that's the whole plot.
Now it's not like this didn't have a ton of potential, but the biggest problem is this one shot written mostly for laughs isn't all that funny. This was written by Evan Dorkin, famous for the indie comic Milk and Cheese. I never read Milk and Cheese, and if this is any indicator I'm not missing much. Each Earth has a different artist doing those pages, and while there are a few big names on here, most of them are artists you never heard of imitating far more well known artist's styles.
The other thing that annoyed me was most of the space was spent on alternate worlds I don't care much about. Most of this book is devoted to the Silver age pre-Crisis worlds. A lot of more recent worlds I would have liked to have seen more of, like the Tangent Earth, Batman Beyond, DC One Million get one panel cameos at most. My favorite bit however was the few pages spent in the 'modern' DCU (this came out in 2000). Check out Bat-Mite's reaction to Aquaman's current look.
There were a few laughs out of this, but by and large the humor fell flat. Given that this usually runs $6-$8 I would recommend passing on it.