Melkor decided to play in harmony with the rest of the Ainur thus avoiding war in the heavens and on the earth.
Cheater! That references the Silmarillion of which no movie has ever been made.
I'm not cheating merely being creative, I've ruined five existing films and one in production by undermining the backstory.
How about these?
Bastian runs right past the bookshop
Peter parker is fatally allergic to spider venom
Buttercup makes the first move on Westley and they move to Australia OR Columbo brings along a book of scripts from the show, it becomes a film about the first case of abuse through predictable storylines
Krypton implodes seconds before Jor-El launches the pod