Audio-Analysis a la Audiosurf

yo! i'm talking about the game audio surf. you have to input an audio file, and the road and points are being generated. my question is: how? audio surf per so tells me, when the song is "intensive" the road goes down, when the song is slow, the road goes up. so does the speed of the rocket. what i really need to know is how are the points generated? it seems like on certain points in the music, the points are set. but how do you calculate this? and what determines the track the point is set? than, the road doesn't go only up and down, it goes left and right too. how do you get when it goes left and right? my theorie is that the x-axis of the road (left/right) is somehow equal to the amplitude-axis. i did input a sinus-wave and the road came out as a spiral.

i hope you did understand what i mean. for all those who do not know the game: http://audio-surf.com