Between missions, you appear in a hub world that is a panoramic scene with several people to talk to and doors to go into. Most of the time, the talks can be skipped and aren't necessary for furthering the story, but interacting with other characters could be fun for fans of the show.
Code Lyoko's audio is present, but not really noticeable. Background music stays out of the way and is not anything you will find yourself humming once the game goes away. Character voices seem to be done by the same actors from the show and you will hear them not only during the levels, but also in the hub world while talking to other characters.