Yeah I like the script. It is a great read. And he squeezed a lot of the ick out. But I'm not sure it would have filmed well. Too much narration, too much tell too little show. I know the narration was deliberate, a translation of the first person voice of the novel to give some of the flavor of Manny. But it was (IMO) overdone. Also some of the plot changes added complications rather than simplifying the plot - often to convey things about character or society that could have been conveyed in simpler ways. Again IMO these un-needed plot complications was a major reason the script ended up with too much narration.
Specifics below in spoiler font:
Manny ending up with semi-recruited as a fink for the Warden, and thus personally being known to Alvarez - time consumer,
Manny being enstranged from his family
While I think a lot departures from the book were sheer genius, I think these two added nothing that could not have been dealt with in a much briefer form.
Also there was one point I think the script should have departed further from the book
the trip to earth. Given that it was diplomatic mission with the object of failing in ostensible negotiations, while moving public opinion towards Luna, would have been better to have someone else handle it. The Manny and Professor De La Paz could have watched some really brief TV clips of critical moments. Manny could have commented: "looks like you chose the wrong man Prof". And the Prof could have replied "no she did exactly right" and explained why.
Why am I so obsessed with ways things could have been handled in less time. Because it comes back to all the weird quirks of character and society that had to be cut out. People rolling double or nothing for the purchase price when they bought something. Professor De La Paz's peculiar form of vegetarianism that let him eat his share of a ham. Not to mention my other point that it would have made room to let a lot of the narrative be replaced with showing what was described in enough detail not to need to narrate it.