I've seen this three times. It's the most clever play, hysterically funny, really laugh-until-it-hurts-funny, but it has to be done by somebody top-notch. Happily, I've only bombed out once.
Michael Frayn suffers from being an all-rounder. I once read some advice he gave to aspiring writers. Find one thing to say and keep saying it, that's what people want out of an author. All-rounders are never respected. Luckily for most writers, they do only have about one thing to say.
Frayn couldn't be further from that. I find it quite astonishing that Noises Off and Copenhagen could both come from the same pen. It may hurt his pocket, but honestly, Michael Frayn, there are grateful readers out there. I hope that is some compensation.