A thoroughly enjoyable animation. And a truly creepy one too. It's fun to see someone else besides Pixar handle character animation so well.
The animation style itself was quite different from Pixar's though. Using much more mocap whereas Pixar's stuff is still a great deal hand-animated.
The mocap worked really well here because it didn't try to match human movement down to the slightest detail, choosing a more stopmotion-style instead. I've always thought of 3D CG as the next generation of stopmotion/puppeteering, as opposed to hand-drawn, so I think it's a really good way to go.
I also liked the rendering style - the GI (global illumincation) again reinforced the “stopmotion” feel.