Can anyone identify this Bach fugue?

[fin9901]

Many years ago, a friend of mine identified the high score music in my Swords of Fury pinball machine as a Bach fugue, but he never specified which one it was. So can anyone identify which one it is? The youtube link is about a minute long and is just the audio of it. Thanks in advance!

http://www.youtube.com/watch?v=jxFRBz8NCzg