Mystery House II is an adventure game in Japanese and the sequel to the 1982 title Mystery House, which is in turn inspired by the 1980 title Hi-Res Adventure #1: Mystery House. Just like in the first game the goal is to explore a mysterious house and discover the treasure hidden inside by gathering four notes that provide clues.

Exploration is similar to the first game, using N/S/E/W to move through the environments shown using a first-person perspective and drawn with outlines. At the bottom commands are entered, such as TAKE, READ or SEARCH. Items can be picked up and used elsewhere to solve puzzles. Compared to the first game the environment is now much larger as the house consists of three floors and the environment can be explored as well.