Double Dragon is the blueprint for the beat'em up genre.
I grew up on the 80's arcade scene and I can pretty well remember the progress especially when it came down to the side scrolling beat'em up genre. Renegade which was released in 1986 was quite popular when it hit arcades, and although it brought a lot to the table in regards to giving the main character so many different moves to work with, along with physically over-powered bosses. It merely scratched the surface on what could be done here. Double Dragon was released a year later and it took a look at Renegade, and improved on that game a great deal in handling its characters. To include DD added two player co-op to its formula which wasn't seen that often in the arcades. To me, Double Dragon was the game that I would compare all games of this type with. It's the blueprint for the side scrolling beat'em up because it came around at the perfect time setting the foundation for many to follow for decades to come. It's quite amazing that you have games in this genre even today that lacks the depth Double Dragon had (I'm looking at the most recent Ninja Turtles games).
Double Dragon has a simple enough story that follows the two brothers Jimmy and Billy Lee, as they make a rescue attempt against the Black Warriors gang to save their female friend Marian whom was kidnapped by them. In co-op mode or solo, the player will travel through four stages putting the beat down on everyone in sight.
From go the players will have access to their entire moves list, with more damaging moves like elbows and jumping side kicks being performed with button combinations. Grappling moves like the damaging knees to the head and even shoulder throw are easy to get out, and there are two nice finishes to striking streams. The two characters come off as bad asses right away and they need to be, because the enemies will beat them to death rather quickly as they gang up on the player/s.
Double Dragon is a very fun fighting game with a few enemy types to deal with. The bosses are quite tough and they eventually make it into the cannon fodder spiking the difficulty. The stages are quite bland in what they offer by today's standards, but when that final stage comes around that all changes with perilous obstacles that hacks away health quickly. The only real draw backs to this game is that the weapons aren't as fun to play with as going barehanded; the only exception is the knife which works as a projectile and deals big damage. The enemy AI is some times hard to hit, as they pause right before head on contact, but this game has one go to move that will always nail them and can actually be spammed through out which always killed the fun for me, therefore I only use it when things get too tight.
This game performs the same I remember in the arcades using a PS4 controller. I had no issue getting the moves out and the small jump section in the third stage had to be just as precise as in the arcade. The visuals were good for that time, and I still like them for the most part because these seem like some nice locations for a brawl, in the day time streets, a factory, and even in the woods. The ending stage feels way too dramatic when looking back, but it still has this majestic feel to it alerting the players that this is the final battle. The game also has some very memorable and fitting music. The third stage is indeed the best capturing the gritty and thuggish atmosphere, personalities, and beef between the characters in this game.
Double Dragon is a very short game that can be beaten within 45 minutes or so which was usually the norm back then. I still recommend giving it a look because it did give the brawler genre something to work with, and it was quite creative for its time. I would rank it rather high in my personal list of beat'em ups though. Definitely try this out if brawlers are your thing or you're interested in older games that helped start something.
The Good: Fighting engine has a great amount of depth, pretty tough enemies
The Bad: Weak weapons overall, one move spam completely defeats game