This movie does Character better than almost any other. Joss Whedon accomplished the almost insurmountable task of combining the six main characters and several side characters in a way that lets each of them shine unimpeded by the others. The brilliance of the one-on-one confrontations each main character gets with the villain that highlight the unique strengths they bring to the team cannot be overstated. It also contains one of the most dynamic and multi-faceted arguments ever put to film. It combined three existing character-based film franchises, reinvented a fourth, and added in two main characters to boot. And it did it so well that it became the gold standard by which all action films and all team-up films are measured.

Closest comparison: It’s the super hero team up movie that started them all

Setting: Super hero
Plot: War Spy
Tone: Action Adventure