I had completely forgotten about the great cast. You've got Samantha Mathis, Jonathan Ward (one half of Mac and Me), Christian Slater, Tim Curry and Robin Williams to name but a few. Ithas the exact same story and principles as Avatar (2010), but set long before that blockbuster. It follows the typical dark elements of animation that I love and is a childhood classic of mine that i'll be revisiting again at some point.
It's not hilarious but Robin Williams does a good job of adding just enough humour to make it work. Tim Curry is excellent as Hexxus, the evil oily substance that is hell bent on destroying the rainforest.
If you like your animation dark and creepy then you're going to love this one. Also check out The Rescuers Down Under, it would make for a great double header with this film.