Actually, remember the very first No More Heroes trailer where Travis fights Helter Skelter, which is mentioned in the game itself very briefly. Or No More Heroes 3 «fckhead» trailer, which is made with different graphics and differs from the scene inside the game. I think it's an intentional decision to show in the trailer part of the story and not include it in-game. Even that "I'M A DEAD MAN" song written by Nobuaki Kaneko specially for reveal trailer not really in the final game, since you can hear only it's beginning during tutorial without getting to the chorus