I honestly can't see why people like these; they are so poorly done and I don't mean the fights, I mean the research they put into it. Even though Deadpool would win against Deathstroke because of his insane healing abilities; Deathstroke would not lose that easily and not act in the way he did, they even gave him the wrong kind of sword. Also, Kirby beats Buu from Dragonball Z, really! DBZ characters are made to be OP, that's the whole point of the show and yet one of the strongest villains gets beaten by Kirby; I'm a fan of all Nintendo characters but thinking realistic towards this, Kirby would never win.
Though, I have never liked crossover stuff because that is not what the characters are about or made for.