The backgrounds look painted in and the animation of both Rayman, his friends, and his enemies as well as backgrounds are very cartoon like. Rayman 2 has got a very interactive cartoon feel about it. The sound effects are pretty good and fit the game well. They don't really standout as anything spectacular. I don't really remember much about them.
Nothing stands out as bad or good.
The sounds of the characters languages are fantastic as I said before. They are unique to this game. The music is great. There are tunes that bring to life the environment you are in. I heard that tune and grew to love it.