The original Double Dragon (1987 in arcades, 1988 on the NES) kicked off the entire beat-'em-up craze. Billy Lee fights through Abobo and the Black Warriors to rescue Marian, and the NES port adds an RPG-ish wrinkle that was fresh at the time.

That wrinkle is the move list. You start with a punch, a kick and a jump, and you earn the rest. Land hits and a heart meter fills; every level of it unlocks something new, from the elbow smash to the hair grab to the jump kick and finally the spin kick. It means the first stage plays like a much worse game than the fourth, on purpose, and it means a player who has put the hours in has a different character.

The port is also famous for what it lost. The main story mode is one player only. The arcade original's whole selling point was two people on a cabinet together, and the NES couldn't manage it: the console can only draw eight sprites on a scanline before things start dropping out, and two player characters plus a crowd of thugs plus a weapon or two blows past that. Technos rebuilt the game around a single player and shunted two-player into a separate versus mode. Kids who had fed the arcade cabinet quarters felt cheated, and fairly.

What's left underneath is still a blast, and it's noticeably longer and better-structured than the coin-op, with a platforming section and a final fight the arcade didn't have.

Elbow smashes, hair grabs, and Abobo's looming menace. This is the template the whole genre copied, and the sequel two years later finally gave it the co-op it was missing.