Sonic 2 CD - What Happened?

Well, this consists of 2 theories, both of which could be wrong, but the more I think about it, the more right it seems.
Firstly lets start with some good faithful magazine pictures:

Sonic 2 for Sega/Mega CD? But where do we go from here? What actually happened?
Well there's also hints Time Travel was planned for Sonic 2.
Craig Stitt: "I do remember something about there being a time-travel story line. I can remember trying to work out the details of what a forest would look like when it was greeen and healthy, then what it would look like after it had been ravaged by Robotnic. I can remember trying to come up with a good way of doing burning trees."
Magazine Article:

So Time Travel was Planned for Sonic 2, and possibly was in an early version of the game, alongside Dust Hill Zone.

Now it's been said in the past that levels were ported to Sonic CD from Sonic 2.
However there has been no conclusive proof for this.
What I think really happened however was that Sonic CD was based on a Sonic 2 Alpha. And was handed over to another team at this stage.
Now that statement, although possibly true, needs conclusive evidence.

Screen Shift

This rather intresting image is from Shacnet.com before it went down. I've heard elsewhere that the magazine pictures are
concept art, but it's still intresting.