Iron Man

The script was not completely finished when filming began, since the filmmakers were more focused on the story and the action, so the dialogue was mostly ad-libbed throughout filming. Director Jon Favreau acknowledged this made the film feel more natural. For example, Tony's monologue while he demonstrates the 'Jericho' in the desert to the troops in the beginning of the movie was conceived on the spot; Robert Downey Jr. isn't just wearing sunglasses for protection from the bright sun, but also to hide the fact that he is reading his lines off of cue cards. Some scenes were shot with two cameras, to capture lines improvised on the spot. Downey would ask for many takes of one scene, since he wanted to try something new. Gwyneth Paltrow, on the other hand, had a difficult time trying to match Downey with a suitable line, as she never knew what he would say.

(at around 1h 23 mins) Stark falls off of one plane and another plane flies through him shearing off its left wing. The plane immediately starts a clockwise roll as if the right wing's weight would cause the right side of the plane to dip. In actuality the plane would roll counter clockwise because the only lift is from the right wing so it would rise.

SPOILER: A scene appears after the closing credits: Tony Stark arrives home to find SHIELD director Nick Fury waiting for him so that they can discuss the Avengers Initiative. This leads into The Avengers (2012) (a superhero team of which Iron Man is a founding member).

German theatrical version was cut (ca. 4 minutes) by distributor Concorde prior to submitting the film to the FSK since they desperately wanted a "Not under 12" rating. Ironically, when submitting the uncut version for the home video release, it was rated "Not under 12" as well, making the cut version even more unnecessary.