Bit of a tangent, but was Unleashed Wii the first time DIMPS made an alternate version of a mainline Sonic game for the lesser systems? I know after this they shifted to handhelds (Colours DS, Gens 3DS etc..), but we didn't see anything of this variety since the Game Gear (Sonic 1/Spinball) variations of the 16 bit titles. Still, to answer the original question, The HD version is definitely my pick just for being the prime version - warts an' all. I kinda treat Wii Unleashed like I do Game Gear Sonic 1 when comparing with the MD original. Both I can play whenever and enjoy for different reasons, but if we're talking Sonic 1, the 16-Bit version will always be the prime game.