I would really appreciate if you guys would watch all of the videos before saying which one is the most impressive.
The game is Beatmania IIDX (Pronounced "TWO D X"), a deluxe version of the original Beatmania game. The original beatmania game is played with 5 keys instead of 7 and the keys are on the left and not the right. You basically play the music in the game, hitting the notes when they come down to the red line. If you don't press any buttons at all, pratically all the sound will be gone and you'll be left hearing only certain parts of the song very faintly. Depending on where you are in the song, each key makes a different sound. So, for a certain measure in the song, each key will play a certain part of the song (Each key makes different noises that correspond to the song's actual sound), when you go to another measure, each key will now be able to play the next sounds.
I had another thread with home videos of myself playing the game (I have the home versions), so, if you won't to see those, just do a search for "iidx." The game has one of the hardest learning curves ever, however, when you get the hang of it, it's quite fun.