"They Are Gone, I'll Move On..." is a piano solo featured in the Sonic Heroes music video/parody "Metropolis Mayhem", put together by the folks at Sonic Paradox! Played along with the Eggman scene during the credits, animated by KaDoYuu, this track is a short arrangement of Sonic 1's Final Zone combined with a short segment of Sonic Adventure 2's "E.G.G.M.A.N.".
Metropolis Mayhem premiered at Summer of Sonic 2013 alongside the 8th and final Volume of the Sonic Shorts.
I would like to add that it was an honour to have taken part in the making of this project! I've been a huge fan of Sonic Paradox since the first Shorts, and believe me, had my younger self foreseen this, he'd scream in ecstatic joy. Seriously guys, thank you so much for inviting me (and putting up with me)! You can't even begin to imagine how happy I was to be taken aboard!
All that said, I hope to take part in the upcoming Casino Calamity music video in a similar fashion (and I'll see if I can contribute anything to the new SEGA Shorts series), because gosh dang, I wanna become more involved with Sonic Paradox since it's been a blast so far!