Yeah, as you say, a game would be the best solution, because it is hard to imagine that in a comic or movie there won't be a winner. The beat'em up video game leaves the story in the background and focuses on the fight. Which can be repeated with no definite answer as to who wins.

If there was such a game, it should be a collection of the greatest heros though, because if there are other random fighters, odds are that Hulk and Superman will be overpowered. So if there was a game with about 10 Superheroes, the weaknesses and strengths could be more balanced. Like Hulk with great strength and Spiderman with great flexibility and Superman with special movements.
If there were other random fighters in the game they would not only be underpowered compared to those heroes but most would probably not use them either.
The concept reminds me somewhat of Super Smash Bros.