Well, I finally watched it...

I was curious about the "inside the giant turtle" aspect of the film, so I watched it for that reason. My verdict is the movie was basically a wasted opportunity. They had a lot of great elements in it, like a unique, Himalayan-style, Steampunk-type society, a fascinating underground world to explore, a few interesting characters, but they missed a lot of opportunities, and there was nothing new or unique to it. In fact, it felt like a lot of cliches from previous Disney and adventure films thrown together, without any heart in the story-telling, or anything to really make the characters truly stand out or reach the audience. Everyone in the story is a stereotype with very little character development (even Splat has something missing from his personality). And yeah, the environmentalism message was very heavy-handed. It would have made more sense for them to find a safer power source that didn't include stupid windmills.

It's too bad. The idea that the underground world is actually the inside of a giant turtle's body was fascinating, particularly incorporating the concept of weird creatures acting similar to cells and microorganisms in our own bodies. It was the only unique part of the film, and again, totally wasted.

And the comic-book part was very dumb.