Halloween sounds christmassy.
X-Files sounds otherworldly and having friendly encounters.
Saw sounds triumphant.
Excorcist sounds whimsical.
Elm Street sounds dreamy rather than nightmarish.
To me the X-files song sound like something out of a japanese anime RPG.
The SAW one sounded like it belonged in a The Sims game.
He has a couple of follow up ones that are also neat.
More horror movies in major key:
And uplifting themes in minor key: https://www.youtube.com/watch?v=9gBvrnNWec8
The Jaws one could be for a movie called "The march of the elephants"
It sounds like music from a Zelda game to me.
Fun Fact: Playing an otherwise happy theme in minor key is actually a pretty common technique used by composers to play the theme during times of conflict or stress for the characters. Empire Strikes Back frequently uses minor key versions of the Force theme and the Main theme to illustrate the uneasy stage of Luke's journey.
or wii sports
I like how the "Halloween" theme has more of a Christmas time vibe to it.