I really struggled to finish this film; I actually fell asleep multiple times while watching it. The actors tried their best to liven up their moments on screen, but Iron Man 2 feels like a complete squandering of both time and money. Several things hold it back: first, the villain Ivan Vanko is awkwardly inserted into the story without any meaningful explanation for his actions or motivations—even Mickey Rourke reportedly felt his character was poorly treated. Second, there’s an unnecessary storyline about Tony Stark needing to invent a new element to prevent some crisis. Third, SHIELD and Black Widow are introduced in a rushed and clumsy way. There's not much that is genuinely enjoyable here, or enough to make up for how slow and boring the film is. It's easy to see why Jon Favreau moved on to other projects.

Source on TMDB