It's a very simple story, but finishes strong. The characters are all really dramatic, and not casual, simple characters; they're all easily unlikable, but the narrative of the story kind of keeps you from really disliking any of the characters. The comedy in this is kind of painful. It feels like the creators don't really know what their strong suit is, which is building the relationship between the two leads, and tries to put in some weird cheesy slapstick-ey comedy that doesn't really work. I watched the first 15 minutes, dropped it, and then came back and watched it all because the opening scenes did not leave a good impression.
Obviously, the animation is not that popular. It's 3D animation. Take that as you will.
I won't be adding this to my rewatch list, nor will I really recommend it to anyone unless you like an ending that feels complete. This movie doesn't end in a wishy-washy way, but has a nice, firm ending.