Rereading the book now. It will be interesting, how they tie in the second half. Like I said, a few events were changed or taken out of order. A lot got simplified and streamlined. The book is broken into 3 parts. Part 1 ends with Paul and Jessica in the stilltent. Part 2 is where the knife fight is. And Feyd-Rautha's rigged birthday gladiator fight. It ends with Jessica taking the test and becoming a Reverend Mother (with Alia in the womb); Paul meeting Chani. Part 3 picks up 2 years later, after Paul has become Muad Dib and has been training a Fremen army while the Fremen work secretly to terraform Dune. The movie is supposed to be in 2 parts and part 1 ends with Paul and Jessica arriving at Sietch Tabr. The knife fight has already happened, but not much of the other stuff from Part 2. So depending on what they cut and simplify, there's relatively little material to cover before the 2 year jump in the story. But I can't see how they can have it happen 2 years later. Paul can't train the Fremen until he's met the Fremen. Lady Jessica can't have a 2 year old abomination until she's taken the test. So in spite of how cleanly they've managed to tell the story without any clunky exposition, at some point--fairly early in the 2nd movie--they're going to have to have some kind of "2 YEARS LATER..." card.