An adult, mahjong game, Mahjong 4P Simasyo features images of live action AV actresses and one actor representing the player. Game play starts with a four player match against three CPU controlled girls. Once the player wins this match he is rewarded with a still shot of a topless model in all of her pixelated glory. The player then selects one of the three girls from the previous match for a one-on-one game. The player then plays against that girl until he defeats her three times or he wins all of her money. Once defeated the girl is shown nude in a low frame-rate "video" of her body bouncing up and down in a suggestive fashion.

After this the player again competes in a 4-player round against the same girls until all three have been defeated in one-on-one matches. Game play then continues with a new set of three girls.