When I rewatched the 2000 Dungeons&Dragons movie I thought it could have been improved by adding a scene where we see some bored 12-year-olds actually playing the campaign. I'd forgotten that that's pretty much what PTerry does here, and it doesn't really help.

There are glimmers of what's to come, and if I hadn't known that he can do much better I would probably have liked this better. But CoM is a mess; no plot beyond "Stuff happens!", some characters he'd wisely revise from scratch, more focus on the cosmology than society... It's Discworld, but not as we know it.