No such trope: redlinked. Tropes need to exist on the wiki before we list 'em in examples. Not sure what this should really be.
Musical Cue: The invincibility theme for the original game is an 8-bit remix of "Sonic-You Can Do Anything", the Japanese theme of Sonic CD. The second game uses a remix of the invincibility theme from Sonic the Hedgehog 3.