7) The Richard Parker Ending – The Amazing Spider-Man 2
It’s clear from early trailers that a lot of material was cut from The Amazing Spider-Man 2, including a subplot about OsCorp spying on Peter for mysterious reasons. A major sequence was also removed from the ending, where Peter is mourning the death of Gwen Stacy, only to be confronted with his long-missing father Richard at her gravestone.
In addition to finally paying off the mystery of his father’s disappearance after two movies, this alternate ending also contained the iconic “with great power comes great responsibility” line that fans had been waiting for. For whatever reason, the studio decided to cut this emotional payoff out so they could tease the mystery for another sequel; big mistake, since there wasn’t another sequel to wrap things up.