This was a fun novelization to read. It took me just over two hours to read it, so it was pretty fast-moving. It has some illustrations before each 'section' of the book to highlight different aspects of the story (I think it would have worked 'better' if they illustrations had actually been with or near the parts of the book where the scene was 'taking place'); while I did not like their placement, I did enjoy the illustrations. As it as for 'young adults,' it really does not add very much to the movie, in my opinion, or to the characters and their motivations. There are some 'interesting moments' where the author does insert something that does add to the story or to the character, but they were so few and far in-between I found myself wishing there had been more of them. One thing that did 'stand out to me' was that there were some scenes in which I interpreted some banter or a moment 'one way' and in the novelization it goes a different way (sadly, I do not remember what they were; I was not in a place to jot them down, either, when I first came across them) (actually, it seems like there was something about Loki that I had taken one way and she presents it differently; there was also something about Tony Stark, but I do not remember that, either).
It retells the movie in a book format, but I am not sure how much added 'depth' it actually added to the characters. The 'action scenes' were fairly short, and I would not have minded reading more 'in-depth character development' or something in regard to the characters. What I would not mind reading is an "adult-oriented" novelization that uses this adaptation as its framework and then builds upon it. I think this author (or another author) could really add to the characters if they were to release a 'fuller' novelization (not only are many of the scenes 'shortened' [such as the battle at Wakanda, described as being the largest land battle on Earth in a while, but it is over so fast that it hardly seems as if such a large battle had actually taken place], but most of the 'stronger' language is taken out as well, which sort of threw me the first time I came across such a change).
It was a fun book to read. I would probably rate it 3.5 stars, rounded down, because I enjoyed it so much (I would not go any higher than 3.5 stars, though). I am glad I took the time to read it.