I never for a moment felt like I was watching a kid's movie. I thought it got a little silly toward the end, but the actual conclusion was fantastic.
Also, Unikitty.
What the fuck? Is it 1999 again?
Looks a bit like Robot Chicken but only with LEGO figures.
They did a fantastic job of making it look like old school stop animation, too, instead of gooey 60hz CG.