Actually, what you want is Sonic Adventure 4, technically. 'Sonic Unleashed" was meant to be Adventure 3 and in Japan, it was called "Sonic World Adventure" I know, seems anti-climatic.
However, I would love to see a new adventure game. Wonderful render! I love all the details you put into this, and the way you did his irises are simply stunning and memorizing. This whole thing is wonderful Great job!
Well it's often considered to be the worst Sonic game in existance, although I've played it and it's not THAT bad. But I wouldn't pay $20 for it (it was a gift from a relative along with Sonic Generations).