For my project the important part was the array of beats and finding a way to detect input in a fraction of time around those beats. It helps to have your song in a DAW to see the percussion layer and base the point in bpm of beats around something on that layer. In the Space Walk level I used the snare. If you're composing your songs you need to be mindful of which instrument you're gonna base the input on, it's part of the level design.