For example, Fox shoots at the screen, Snake, during his final smash, shoots over his shoulder while facing the screen, etc.
I'm not sure if the animation is shared with anything else, but the one when characters smash into the screen would be neat to change to something humorous (a character waves as they fly past, someone claws at the screen trying to grab onto something to avoid falling, or gimmicks involving weird body parts/ accessories hitting the screen, (Mario's hat falls past the screen, with Mario falling a second later), etc).