Tato posted:

Highlander series is the greatest example of all of this because the first film is perfectly constructed to leave no room for a sequel. There are immortals, there can be only one, all of them fight and at the end only one is left and he has the prize. It ties a beautiful little bow on the whole thing and is indicative of a time when people cared about making a satisfying film more than sequel/franchising potential.

Each unnecessary sequel has to completely re-write the first film in an insane attempt to justify its existence, after which the NEXT sequel also ignores that one.