If you're a fan of music/rhythm based games along the lines of Guitar Hero and DDR, you might be interested in this game. This game dates back to 1999/2000 and was one of the first music simulation games ever created (DDR was the second, at 1998, and beatmania I was the first, at 1997).
The game consists of 7 keys in a piano form (4 white keys, 3 black) and a turntable. You can compare it to Guitar hero, but the notes scroll downward in stead of towards you and there's no strumming involved (duh XD)! Modes include your regular single play, battle (which is like co-op in Guitar hero) and Versus. There is even a doubles mode where one person uses two controllers, making 14 keys and 2 turntables.
The game is based on a level 1 to 12 scale, 1 being easiest, 12 being hardest. Difficulties depend on which game you play, as earlier styles call their difficulties by light7, 7keys, and Another7 (or light14, 14keys, and Another14 if you play in doubles) and later styles (including the US release) call their difficulties by Normal, Hyper, and Another. There is a beginner difficulty as well, where songs are only rated level 1 to 3 and it has an easier life bar. To pass a song in the game, you must finish a song with your life bar being above 80%. Your life bar will never fall to 0% (unless you play with a specific mod called "Hard", but that's for a later time) so you can never really "fail out" of a song (unless you exit out of it of course XD). This game is notorious for it's extremely tight timing (that's so tight that even some of the easiest songs haven't gotten perfect scores) and steep learning curve. Definitely one of the hardest music games in existence.
The music in the game is mostly in-house, or songs created specifically for the game. When it originally started, the song genres were mainly techno, trance, and hip-hop, but since has evoved into various styles of rock, electronica, classical remixes (if you've played DDR, you may recognize the song called "V"), and even their own made up genres with names like "Esoteric slowcore" or "Deceptive gabba". Over 1000s of songs total, it's sure to have songs that please you. Also, every song has its own unique video to go along with it, and home versions contains a gallery mode, where you can unlock several pictures drawn for the game. Very eye-catching!
Since it's release, there have been 16 Arcade versions and 12 Home versions, including one US release (under the name "beatmania"). Arcade releases have well over 100 songs, with the latest having near 500 songs! The Japanese home versions have near 100 songs, with the latest having 95 songs. The US beatmania release was a compilation of several IIDX releases from the 1st release to the 9th, and some older beatmania I songs. A little over 50 songs total and very good for an introductory game and beginner friendly (despite the awful purple theme XD). If you are a fan of music games, i'd recommend modding your PS2 (can be done for very cheap) and checking it out, or if you can find it, pick up beatmania for the PS2 (look for the rectangle purple box). Usually only $20-30, which considering you get a controller and a game, is a very good deal, when the Japanese controller alone normally costs over $60.
Pictures of the controllers:
US style controller-
Japanese style controller-
Arcade style controller-
So here's some videos:
Videos of some of the easiest songs in the game-
Videos of some of the hardest songs in the game-
http://youtube.com/watch?v=yW34iG4bsQw (autoplay, meaning computer plays the song)
Some videos of me playing-
To those who have played before, here's a IIDX thread lol.