Roommania #203 is a simulation game first released for Dreamcast in 2000 and later released on PlayStation 2 in 2002. It follows the life of Neji Taihei, a student living out a mediocre existence in Japan. The game is described as an 'intervention' simulator, where the player takes the role of God whose task is to make Neji's life more meaningful. The game's writer and composer Tomoko Sasaki cited an obsession with internet webcams as her inspiration for the game's story and mechanics. A sequel was released for the PS2 in 2003, New Roommania Porori Seishun.
The main difference between Roommania and other life sims is that the player doesn't control Neji directly, instead the player is a god and needs to make Neji notice something in the room so Neji can interact with it. There are two different ways to interact with the room if Neji isn't home, the player can interact moving stuff in the room or reading his diary. While Neji is home he has a queue with different tasks, like smoking, watching TV or chat on the computer, in order to change the priority or add new tasks the player has to throw ping pong balls to the object in question if its done too quickly Neji will get irritated and wont pay attention. Either one of those ways to interact with the environment has a time limit. To progress in the game the player needs to complete different missions, these missions are given through short cutscenes with a little clue in text, for instance, in one of the missions the player needs to read Neji's diary when he is not home, the name of the missions is "While the demon is out" (鬼の居ぬ間に). If the player fails to complete the mission it may lead to a bad ending.
The game features music from the fictional pop idol, Serani Poji, which was created by Tomoko Sasaki, the writer and composer of the game. The game also featured Radio DC, which was a fictional radio station that played music from other Sega games like Panzer Dragoon Saga and Burning Rangers. Both Serani Poji and Radio DC would see releases as their own albums.