I played the demo on Wii U.
Truth be told, between yesterday and today I played it 3 times, just for the pleasure that the interaction with this world gives you.
It's really ad outstanding masterpiece for what I see so far.

I'd like to share my feelings about the first level of the demo.
I was playing it for the first time, and when I had to switch to murphy and partner with an AI, I felt a little too out of control.
I know these multiplayer levels are optional in order to complete the game, and that the different approaches are going to make this game even more relevant, but I have a suggestion.

When I realized I could use a wiimote for a second player, and control Murphy on the gamepad, I played through the level controlling both: I moved Ray with the wiimote and sometimes used Murphy for interaction on the Gamepad (to do so I put the Gamepad in front of me, on a little table).
The experience was amazing and perfect, except for the moment when I had to tilt the gamepad (I had to put down the wiimote for a moment).

Of course these levels where designed for asymmetric multiplayer, but why not give the single player experience some more spice?

So:
1_ maybe tilting could be also mapped to a circle stick
2_ Even further, in single player maybe I could just play on the gamepad with sticks and buttons using Rayman, and also have the screen enabled for Murphy interactions at the same time. I could use both characters on the Gamepad and have a thriling single-player experience.

I must say that the level was also enjoyable using murphy alone, and the AI is very competent when taking control of Ray, but I'd like the extra options where possible.

This game, anyway, is far beyond my expectations and I'm going to buy it on day one.