You find yourself lost in a mysterious space in the underground shopping area of a certain building while trying to have lunch. Clear the game presented by someone and aim to escape from the eerie underground shopping area. B1 is a simple horror walking simulator with a rule to turn back when feeling something strange and to go around the underground passage if nothing seems to happen. Clear this game the specified number of times and take the elevator to B1 to escape. Among the occurring changes, some can be checked and collected. There are also achievements that can be obtained by collecting everything, so please give it a try. You can change settings such as field of view and mouse sensitivity.