Movie is also great. It's just not finished. :(
Yeah, once you get to the end of the first half, it's like oh crap, we're out of time, montage montage, end battle, fight with Sting, plot plot plot, end credits. The film that's supposed to be released this year is reportedly only the first half of the book; I guess we'll see how that goes.
Standard 3-act structure has a natural breakpoint at the midpoint twist of Act 2, not that my recollection of Dune is detailed enough to confirm that it maps naturally to 3-act structure in detail.
This actually reminded me of a colossal mistake made by Hobbit pt.2 movie, when they ended the part with a dragon flying away to burn the city after the cringiest of chase scenes.
They could have easily end the part with slaying a dragon, and then show it again in part 3. All they needed was to find a different POV character!! One dragon kill, shown twice.
Assuming this game is like the Dune II computer game: you don't need any familiarity. For example, House Ordos (one of the three major houses in the Dune RTS games) isn't even in the books if I recall correctly. I grew up playing (and loving) Dune II (and all its sequels) long before I ever read Dune.
As others have said the controls have aged fairly badly if you're used to all the quality-of-life improvements in modern games.
Having played the game will in no way spoil the books.
How familiar with the books do you need to be to play this?