Activity

Well, what I noticed is the dichotomy between some characters who were willing to sacrifice individual lives for their mission (Thanos, Vision sort of) and others who were willing to compromise half the people in the world for their friends (Gamora, Dr. Strange, Loki, etc.).

Of course, there was also the emotional value: getting the audience to be emotionally invested in characters then tragically killing them off.

You cannot avoid character development in a book. Infinity War‘s only new main character was Thanos, and I think he was developed very well. His motivations and even emotions were made very clear. However, there were countless other characters present, and none of the other characters were developed much in the movie, which was only able to work because they had all been introduced in previous movies. I think this is harder to do in a book though (it might work in a series), especially when you have as many main characters as there was in Infinity War.