So I finally took some more time with it and I think it's one of the weaker 2D platformers I've played on the Wii.
First of all, it looks gorgeous, better than any other 2D platformer on the system. Still, it's sometimes hard to see whether some objects are in the background or whether they are part of the player's layer.
In addition, the controls feel a bit weak, which might only be a problem of using the Wii Remote+NunChuk combo. Jumping and flying does not always work as intended as both actions are mapped to the same button. There's also the problem of doing a walljump when I actually don't want to do one... [Using the Wii Remote is out of the question as it renders the game nearly unplayable in the water and flying sections].
Moreover, the collision detection is weak. Sometimes I was hit by a fireball when I was still quite a bit away. Also, at times it was pure luck whether I could jump to the platform above or whether I couldn't, both times it looked more or less the same. Even worse, Rayman could grab some platforms while he couldn't grab others - I've yet to find out how this is meant to work.
But these are all small issues, the main problem I had was that I found it absolutely boring. I loved Super Mario World, I appreciate NSMB, I love Wario Land, and I even enjoyed Kirby Epic Yarn - but I just don't feel the love for Rayman Origins. I've finished 7 worlds now and there's just a huge lack of challenge - and I'm a rather bad gamer.
Perhaps the title is great fun in multiplayer, my sister assured me that's the case. I will finish up the main game and then I'll take a look at the time challenges. The levels I liked the most were those "high speed" levels in which you build a rainbow to the next world or something like that. I would've also greatly enjoyed the follow-the-chest levels, if it wasn't for the flaws mentioned above.