Ah, reminds me of my High School Days of Infamy.
Well maybe not, but River City Ransom was a very good 2D side scrolling beat'em up game on the NES. This game was so much fun due to the fact that, personally, it was humorous.
As for a beat'em up game, it's the only one that I could recall in being unique in powering up the player's characters. This was an ingenious way to add a different type of game play element to the game. Of course taking place in a town, the game makes use of the shops to offer power ups.
Recommendations: If you like old school beat'em up type games, I'm sure you'll enjoy this game.