This NES title screams for Co-op multiplayer and doesn't deliver! One of the worst ports from ARC to NES.
Honestly, standing alone the game wouldn't have been that bad if it was not a "Double Dragon" game. The fact that you actually level up and acquire new moves is a nice addition that was not in the original game. If it had been titled simply "The Dragon" or "Billy's Revenge" I would have less problems with it, because I would expect something different. But really, the only thing "Double" in it are the "baddies" that come in pairs to take you out. I thought it was kind of funny how there's always no more than two bad guys on the screen at a time. I don't fully understand how the NES works since some games have huge frame rate problems while others have the screen packed with animation and seem to have no problems. For example, Double Dragon III has an incredible amount of animations going on at once, and it doesn't have any hiccups. And it's co-operative! I don't get it.
There's really nothing else to say other than that this is not "Double Dragon." It may have Machine Gun Willy as the final boss, but that's as close as it gets to being "Double Dragon."