Still see Double Dragon get slated with comments about how much better Final Fight is, people seem to forget that back then 3 years was a long time and things changed fast so it should be better really but Double Dragon defined the multi directional side scrolling Beat Em Up
Renegade before it which I love also gave you multi directional but within an area, but you have 1986 Jail Break which is also is mutli directional side scroller but Run and Gun style, is there any earlier examples of that or was it a first? but look at the difference between Jail Break and Double Dragon GFX wise
Double Dragon was amazing on release, yet when I hadn't seen it for a good few years and been used to playing later games like Virtua fighter, Mortal Kombat... popped in Skeggy Arcade and some disappointment set in as I had a go on it after probably 5/6 years, you have to look at when it was released, what came before it and how good was it at the time of release and nothing touched it just like Operation Wolf

Still be one of my Go to Games for fun along with Renegade, If I had space I'd built replica cab to sit next to Double Dragon with the Marquee, Monitor Bezel and get a CPO done for Renegade