Looks like someone has leaked 18 music files from Sonic 4 onto the net.
If you go to the official site for the speedy blue one, you can download a legitimate version of the Splash Hill Zone 1 music. While there, you will notice that three more music files have been locked.
Music from the following zones are included:
- Splash Hill Zone
- Casino Street
- Lost Labyrinth
- Mad Gear
- Special Stage
- Boss Music
- Final Stage
If you like Sonic music, well, you'll love what you'll hear probably.
Sonic 4: Episode One is slated for summer on PSN, WiiWare and XBLA.