Absolutely amazing.
Seriously, this reminds me of those flashback videos. The video in my head is something like...
*Robotnik finally is going to die. That's the piano bit. Then, he remembers when it first began. On with the flashbacks, the illusions of grandeur, the pain, the tears, the memories... The the piano bit comes back and Robotnik dies.*
Sometimes I have the "Robotnik playing piano then goes to club and makes a rave song" video, but mostly it's the flashback one.
I'm a sucker for songs like this. I haven't meant one I didn't like yet.