Controls
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: Press left or right to move backward or forward. The screen will only scroll when you move forward, and since enemies keep coming whether you move or not, you can progress at your own pace.
: Press down to crouch or duck under attacks. Punching while in crouching position produces a low punch, while kicking produces a low kick.
: Press up to perform a high jump that can dodge most enemies' attacks. Combine the jump with a direction to jump forward or backward, repositioning yourself against any number of enemies. A kick can be performed while jumping, but a punch can't.
- , : Press down, then up quickly afterward to perform an even higher jump.
: Press the 1 button to perform a punch. Punches don't have good range, but are more powerful than kicks.
: Press the 2 button to perform a kick. Kicks are quick and have good range, but are weaker than punches.
- + : Press up and the 2 button simultaneously to perform a jumping kick. Like its grounded variant, the jumping kick is weaker than a punch, but its high maneuverability can prove incredibly useful against bosses.
Player
In Black Belt, the player controls Riki (pictured to the left), a master martial artist in a post-nuclear war setting whose girlfriend, Kyoko, has been kidnapped by Wang. Wang is a rival of Riki's and has undergone similar training, making him something of an equal in skill. However, before Riki can confront Wang, he must overcome the challenges presented by Wang's gang of martial artists, each assigned to different areas. The strongest of these areas are what comprise the stages' mid-bosses and final bosses.
In Hokuto no Ken, the player controls Kenshiro (pictured to the right), the sole successor of the legendary martial art Hokuto Shinken. Kenshiro's story also takes place in a post-nuclear war setting, though the environments traversed by him are vastly different from those traversed by Riki. While his quest is similar (to rescue his girlfriend, Yuria, after she was stolen away from him by his rival, Shin), it's made all the more complicated by the puzzle of Yuria's true location and the variety of enemies that stand in his way, all of which have goals of their own.
Riki and Kenshiro share a move set (punch, kick, low punch, low kick, and jumping kick), and common enemies even explode when Riki punches or kicks them (a trademark of Hokuto Shinken). While Riki and Kenshiro are represented by small sprites in the stages' main segments, in which they punch and kick common enemies and mid-bosses, they are represented by enlarged and more detailed sprites in the boss fights. These one-on-one fights are true tests of Riki's and Kenshiro's ability to adapt, as they require strategy and quick reflexes.
Health
Riki's and Kenshiro's health are represented by a yellow health bar at the top of the screen. A small sliver of health is lost when hit by a common enemy, while a bigger chunk of health is lost when hit by a boss. Health can be recovered in both Black Belt and Hokuto no Ken by defeating mid-bosses, and all health is restored upon the confrontation with the stage's final boss as well as following it. However, Black Belt presents more opportunities for health restoration in the form of sushi, floating in the air and scattered throughout the stages.
When all health is lost or time runs out, Riki/Kenshiro lose a life. They begin the game with three, and gain an extra life for 100,000 points and 300,000 points. When a life is lost, the game is restarted from the nearest checkpoint (either on the path to a mid-boss or at the start of a stage's final boss fight).