Hi ShaBloip,
Look more closely at that JSON... it is actually returning just one song. That song just has lots of tracks on it, reflecting the fact that the same Karma Police audio has been released a bunch of times, and appears as a lot of different tracks in Spotify.
This will be more obvious if you leave out the bucket=tracks from the request (so you don't get back that detailed track-level information at all).
-Eli