Unsurprisingly, this volume of the Stranger Things novelizations cuts out the most, since it's the densest season with the most disparate plot threads. The Hopper and Joyce story is barely there, with the focus on the Hawkins and Lenora groups, as you'd expect from a novelization aimed at younger kids.
For this installment of 'weird editing choices', we get zero mention of Argyle's smoking habit, but he does still randomly fall in love with one of Suzie's adopted sisters. Dropping the 'junior' from the title does mean they get to address all the deaths pretty head on, though.
The description of what happened to Henry in respect of the Mind Flayer when he first got to the Abyss feels a little wrong, but I guess we'll see how they reconcile that in the final volume.