The film is shot in a whopping 144 frames per second. A gizmo on the projector flip flops between each frame and polarizes the image clockwise and counter clockwise. You wear glasses that look like nurdy 50s sunglasses.One lens is polarized clockwise the other counter clockwise. Each eye is seeing 72 frames a second and 72 black images in between. It's so fast you can't percieve it. If you live in the US with 60 cycle current or the UK with 50 cycle it's like trying to watch a fluorescent bulb to see when it switches off. Circular polarization also means you can tilt your head at angles and the image still comes through. It doesn't dim when you turn to grab the popcorn.

So what does that get you. Like Rayraz says, parts are overdone. The little seed thingies float to within arms reach, but you are constrained by the square screen. They disappear abruptly at the edge when you should still see them floating in the theater. The action starts you don't have time to pick it apart. When the characters are running across a tree limb they are running across the tree limb. You can look over the side and focus down to the ground. You can look at the bird flying off or the higher branch they passed under and they are all real at different levels and focal lengths.There are parts up in trees,over waterfalls, climbing floating islands, riding sky birds.Seriously, If you have a fear of heights 3D may be too much for you. It's that good!