Proun's graphics are full 3D, yet very minimalistic. They get the job done, and are ok to look at, while not distracting you while you zip by.
The semi-jazzy music isn't something you'd buy a CD of, but it fits the game like a glove. It's perfect for giving the full experience, so I wouldn't recommend playing the game without music.
Proun's really simple. You're a ball and race others, twisting around a wire to avoid any obstacles. Accelerating for a while without hitting anything, you'll get boosters. It's amazingly addictive, even with the limited number of levels. There're user-made levels available.