Hardcore movie fans as opposed to regular movie fans are extreme fans who watch a specific movie numerous times and love to discuss/debate the specifics of the storyline, characters etc. They are also less willing to accept changes/remakes/sequels to a particular movie unless they are of a similar high quality, since it is the high quality of the original/originals that made them a hardcore fan in the first place.
hardcore movie fan - "My friend is a hardcore Star-wars fan. He is constantly discussing the plot details and has lost count of the number of times he's seen the original trilogy. He anxiously awaited the prequels, but was dissapointed at how they turned out.