It's interesting to consider how all of the significant characters would interact and contribute to the narrative in a film like this. Everything clicks well together. Although, as one might anticipate, R. Downey Jr.’s presence feels quite important, the character dynamics are generally balanced, and I believe that the most memorable moments come from scenes featuring the digitally created Hulk. Considering how effectively they’ve combined characters—including big-name actors and computer-generated figures—it's really a testament to the writers and director that this film turned out so well.

Source on TMDB