Kung Fu was one of the earliest NES games, and it's a foundational beat-'em-up. You're Thomas, climbing five floors of a tower to rescue Sylvia from Mr. X, punching and kicking through waves of grippers, knife-throwers, Tom Toms and dragons.

It started life in arcades in 1984 as Kung-Fu Master, and it's a licensed game, which almost nobody realizes. Irem had the rights to the Jackie Chan film released in Japan as Spartan X, and the Japanese cabinet carries that name. The five-floor tower, the girl at the top, the henchmen on each landing: that's the film's final act, turned into levels.

The design credit is the part worth knowing. Kung-Fu Master was made by Takashi Nishiyama, who went to Capcom a few years later and built Street Fighter, then left for SNK and built Fatal Fury. You can see the thinking here already. Thomas has a high attack and a low attack, enemies have to be answered with the right one, and the floor bosses have patterns you learn rather than health bars you grind down. Strip away the side-scrolling and you have a one-on-one fighting game two years early.

The economy of it is what makes it replayable. You get two attack buttons, a crouch, a jump, and a timer, and that's the whole vocabulary. Grippers latch on and you shake them off. Knife-throwers make you choose between ducking and jumping in a corridor with room for neither. The tower gets denser rather than more complicated, and reaching floor five the first time feels like something you did rather than something you were shown.

For a launch-window cartridge it holds up shockingly well. Sometimes simple and tight beats big and complicated.