How about the best side scrolling beat em up of them all? Streets of Rage 3
Or better yet, give the fanmade Streets of Rage Remake V5 a go. It's so good, SEGA had to terminate the download links for it. A fanmade game that they approved themselves before it was completed But if you want something else, a co-op run of Battletoads for the Arcade is a good choice. Or Muramasa: The Demon Blade for the Wii. A little modern, but it's beautiful.