Very Good
I ADORE the great animation here, and the music is phenomenal. Bear Bear is an adorable, tragic character, and the chase scene at the end had my heart pounding.
I do find the story itself to be pretty cliche, though - "a child gets a new toy that turns out to be evil" has been told a lot of times. Also, I could have done without the intertitles from Bear Bear's inner mind - I think the film would work even better if it were completely silent.
That said, you clearly spent a lot of blood, sweat and tears on this, and I commend you on a great job.