Walk right. Mash on the punch button. Walk right. Mash on the punch button. Walk right, mash on the punch button. Walk right, mash on the punch button. Walk... yeah you get it.
Before Street Fighter II enslaved millions of ardent arcade dwellers, Final Fight had us pumping countless quarters into a side-scrolling brawler that looked and sounded better than anything else in the bowling alley/pizza parlor. But that's all it had, a better presentation than other arcade games of the day; big meaty sprites pounding the crap out of each other were more than enough distraction from brain dead gameplay. Once arcade games evolved past stiff animation and identical level design, we all abandoned Haggar, Cody and Guy for more entertaining endeavors - but you'll still hear people talking about it like it was genuinely fun.
What we remember is not fun, but a sea of copycat games that also incorrectly assumed this was a good gameplay model to emulate. Cue a decade of conceptually bankrupt titles that would never have cluttered and choked out arcades had we all realized early on how effing boring Final Fight really was. Some later, licensed games, like X-Men and TMNT masked the monotony with hot properties and maybe a new move, but even then you eventually realize mashing on one or two buttons for hours is a horrible way to game.
On the other hand, Final Fight made Capcom a huge heap of cash that probably went into Street Fighter development, so maybe it was worth it after all.