Sega’s Digital Brand Manager Ken Balough has confirmed on the Sega forums that Sonic 4: Episode 2 won’t be coming to the Wii. The original Sonic 4: Episode 1 was available on Wii but the latest episode will be coming to Xbox 360, PlayStation 3 and smartphones only.
The reason Episode I was on the Wii was because we wanted to bring the Sonic 4 saga to the widest possible audience. Episode II unfortunately will not be coming to the Wii – for reasons most people have probably guessed, but that doesn’t mean the SEGA isn’t supporting Nintendo platforms, we have a very strong partnership and will continue to do so.
Here's the teaser trailer Sega released yesterday