I picked up Rayman Origins when Amazon had it on sale right before Christmas and we've finally got a chance to jump into it. My first impression is that it's a beautiful game with a very fun art style and a great soundtrack. Kian also laughs nearly the entire time we are playing.
The mission lengths are quite short, maybe 5 mins or so each...but that is perfectly fine. The action requires precision movement and quick responses to get the maximum amount of stars by the end so you are ready for the break when it comes.
One of the things I found disappointing is that the second player doesn't get achievements. This is something I need to research a bit because I'm not sure why this choice would be made. I know we had this same issue with The Simpsons Game, but that was just because Co-Op wasn't part of the Godfather engine we were using.
We're having a lot of fun with it and I'm curious how big the game is. I'll add some more comments as we get further along in our play through.