Karateka uses gameplay elements found in both side-scrolling 2D platformers and fighting games. The player is introduced to the unnamed hero as he ascends a mountain into Akuma's fortress to rescue his beloved, the Princess Mariko. As the player directs the hero into the fortress, various foes will appear and attempt to stop the hero. The player must have the hero, normally in a run stance, enter a fighting stance before engaging in combat, otherwise the hero will be easily killed by the enemies. Once in a fighting stance, the player controls the hero to deliver blows, punches, and kicks at the enemy while dodging the enemy's own attacks. The hero's health, shown by a bar on the bottom of the screen, diminishes with every hit he takes, though health can be recovered slowly by not engaging in combat. Should the hero lose all their health, the game is over, requiring the player to start again. Similarly, the enemy's health bar is shown on the screen as well; once this is drained, the player has defeated the enemy and can progress forward. In addition to human enemies, Akuma sends his trained hawk infrequently to attack the hero, which can be deflected with an appropriately-timed punch. There are some environmental hazards that the hero can fall into, such as a falling portcullis or an open cliffside, ending the game immediately. Throughout the game, cut scenes using the game's animation are shown, such as showing Mariko nervously awaiting her fate.