There are 6 huge environments and 1 smaller environment that all look superb. Each one has a different theme so they all are unique. Half the fun of reaching each new island is the ability to fly around and just look at every corner of these fantasy lands.
One thing that Glu has done well is give a good sense of speed. When you are gliding slowly you can't really tell that you are even moving, but as you build up speed the air surrounding Eryn gets blurry just like the racing games. This is a great effect and just adds that little bit extra to the game.