I finally started reading
Who Is Killing the Great Capes of Heropa? (by Andrez Bergen), and I'm about a third of the way through it.
As one would expect from the title, it's about a city where superheroes are getting killed off. The trouble is, there's a lot about the first fifth of the book that doesn't make much sense - but then, when the reader is belatedly clued in to something all of the characters know, the puzzle finally comes into focus. I'll put it in a spoiler tag, but I regard this more as Very Useful Information - to the point that I've considered restarting the book so I can apply the missing knowledge to that first section.
I do not intend to malign the book - I just wish the author had mentioned this info much earlier. Not doing so made the book appear much more poorly thought out than it actually is.