Auditorium is an abstract puzzle game in which a stream of particles must be manipulated with tools on each level, which are movable and resizable circles, to cause the stream to cross various hot points on the screen. The basic tools will change the direction, and can be made stronger (and to have a larger range of manipulation) by increasing that tool's radius. Other specialized tools can do things like splitting the stream or changing its speed.
As well as hitting the hot spots, many levels also include colored areas, which are required to change the color of the stream to activate like colored hot spots.
In addition to being the goal, each hot spot is a track of a musical composition (which is different for each group of levels), and when it has been activated, it will play that track. When all the spots are active, you complete the level, and can, if you like, listen to the music playing before moving on to the next level.