I was gonna argue that ULTRAKILL has the least calm intro because it immediately had you fight several really fast demons and then the f**king Easter Island rock as a miniboss in the last room,
but Dead Space 2 definitely had a less chill intro.
Moments after the intro, you find a man who cuts your straightjacket free, says that all the necromorphs are because of Issac, then slits his own throat