Sonic Megamix - Dark Fortress Zone Acts 1 and 2

So here&a routine run of Sonic Megamix with Shadow. However, my copy might be a wee bit different than yours. See if you can figure out what&going on by the end of the vid. Megamix forum topic: EDIT: The song (which won&be in the final) is THE HYBRIDFRONT ~SCARAB MIX~