Even though the thought of crossing Indiana Jones with E.T. is a bizarre combination, it does match the time period the movie is set in. In 1957 there was speculation about extra-terrestrial life on earth. Aside from it, the movie brought back that classic style that only and Indiana film can deliver.
Downey's adaption to Tony Stark was almost flawless. Eye candy for any viewer. With it's bad @$$ hero, villain, and soundtrack, Iron Man becomes a hit amongst many failed Marvel adaptions.