system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 Citizen Kane is such a big deal in film.

I hear a lot of talk about the movie and would like a little primer before I jump in and watch it.
gpt
It's considered big in part because Welles was an innovative cinematographer that really used camera angles in new ways and to give the movie depth. 

It was also fairly controversial in that it was based on William Randolph Hearst, who owned like half the papers in the country at the time.