Iron Man 2

Scarlett Johansson dyed her hair red before she even got the part of Natasha Romanoff, a.k.a. Black Widow, because she wanted the role so badly.

(at around 1h 3 mins) When Nick Fury and Natalie Rushman are with Tony Stark and give him a vaccination to cure his blood from poisoning him, Nick Fury gives him a syringe filled with what he says is "Lithium Dioxide". However, lithium ions have a single positive charge while oxygen ions have a double negative charge. As such, lithium oxides have two atoms of lithium per atom of oxygen, not two atoms of oxygen per lithium as "Lithium Dioxide" would suggest. In addition, any oxide of lithium would decompose immediately in any kind of water solution, such as would be required to inject it into a person.

There is a scene after the closing credits: Agent Coulson arrives in New Mexico and locates a crater in which lies the war hammer Mjolnir. This was a contracted version of the same scene from Thor (2011).

The mainland Chinese release obscures Vanko's nationality by reversing all Russian references on the soundtrack. For example, the word "Russia" comes out as something like "Ashar", and "Siberia" as "Ayuribias". The subtitles and the Mandarin-dubbed version simply delete these references altogether.

Edited into The Rotten Tomatoes Show: Alice in Wonderland/Stolen/Brooklyn's Finest (2010)