Yeah after getting more feedback I realize that I probably set the threshold too high. I figured people would get it by just running around.
You "dance" by just pressing a lot of buttons quickly (WASD + Space). With a lower threshold one could probably figure it out easier, but as I said, some here in the comments and a few friends had serious problems figuring it out. Good to know for future games.
But I'm glad you had fun. Thanks for the feedback!