Not really a game system by itself, more of like an add-on. Similar to a Dreamcast VMU, this little unit stores gamedata like a memory card. But there are certain Playstation games which allow you to play a little mini-game with the pocketstation. Sometimes the game you play on the pocketstation can alter the game on the PS1, like developing a character for an RPG for example. Too bad this little thing was never released in the states, it would have been a neat little gadget. I'd get one but then I'd need to mod my Playstation to play Jap games to get any use out of it. Not very rare but kind of expensive, run about $35 -$40 on Ebay although I've seen them on import game website for half that much.