Here's an opinion:
Sonic Unleashed opening > Sonic Riders opening > Sonic CD opening > Sonic Adventure opening > Sonic Colors opening > SA2B opening > Sonic Mania opening > Sonic Heroes opening > Shadow The Hedgehog opening > Sonic Generations opening
Sonic Unleashed opening > Sonic Riders opening > Sonic CD opening > Sonic Adventure opening > Sonic Colors opening > SA2B opening > Sonic Mania opening > Sonic Heroes opening > Shadow The Hedgehog opening > Sonic Generations opening