I have the original version on the Megadrive, and I gave that a very respectable 9.0 in my review. I decided I would at least try the game on XBLA to see what the differences were.

Apart from a few sound glitches, this is an AMAZING version. Let's see why:

• Acheivments: I looked them up, and they seem really well suited to the game. They really do push you to complete the whole game, and they are very doable, but not too easy.
• Controller: Like many Megadrive games, the A and C buttons were often just used for the same thing, and with Sonic, all three face buttons just jumped, and I was never really feeling quite comfortable with the MD controller. The X360 controller just has the very obvious A button as jump. That is it.
• Save: You can save the game. Huge plus for me, as I don't really wnat to play through the whole of Sonic over and over.
• Slightly smoother graphics: There was absolutely no slowdown or flickering like there was in the original.

I like it so much, and its only 400 points, that I may actually rebuy it!