It's a lot better than I was expecting. After Snuff I was expecting complete garbage as Terry's writing has got much worse.

I have no idea how much Terry contributed to this piece. I can tell you when I reached Chapter 48 I suddenly recognised what I'd been reading. It's a basic rehash of bit of Strata and Dark Side Of The Sun.

There are a ton of 2001, A Space Odyssey jokes. Lots of them people who haven't read the book or seen the movie might miss. I can't comment on Mark Twain jokes (apart from the terrible numerical one that totally doesn't work and never will), I'm not familiar with the mans work so if he is spoofed, I missed it.

I assume Lobsang is named on purpose to sucker in the Discworld fans.
I found the irony of Joshua, I assume one of the two writers is a Wargames fan.

The book is an easy read, you can finish it in a day with no problems.

Expect to want to read it again to see what you missed.