I'd just like to share that this was my first ever Discworld play. Our local group picked it for their spring production last year, sight unseen, and none of them had ever read a discworld book in their lives! I ended up getting roped in as an adviser and then co-opted on stage because there were more characters than actors.
To try and explain the Shakespearean undertones, then the Discworld overlay, then Stephen's abridgements, followed by the complications of cross-dressing due to a surfeit of actresses (e.g. Tomjon & Verence II) left the cast utterly convinced that the whole thing was a mistake. Most of the 'jokes' bypassed even the actors who gave them, despite my best efforts. By the time we did the dress rehearsal I just wanted to crawl into a hole & hibernate
We musty have done something right, though, the audiences not only laughed every night, they did so in all the right places for the right cues
A number of the 'actors' still couldn't work out why, though