Jan Jaka Jan is a mahjong game in its core, the majority of the gameplay dedicated to mahjong matches (two- as well as four-people) against a variety of opponents. The player can navigate the protagonist around the top-down town and enter various locations, which are viewed from first-person perspective.

The player is also able to buy items to increase his parameters during mahjong matches and encounters of sexual nature.

Cut scenes occur before and after mahjong games, and many matches and other events are dictated by the story. Defeating a female mahjong opponent usually leads to cut scenes that depict nudity and sexual situations.