I'm not a big fan of the song, but it's definitely not bad, like 6.5/10. But the use of animation with it works really well. I feel like there's a bit too much recycling of work though. The walk cycle is so short that its constantly looping just comes across as lazy where as the obvious intent is to showcase the monotony of the journey and the bears determination. The sort of sloppiness to the style of the drawings works in it's favor but only so much. When such a central part of the animation is "walk to the right", you need to try drawing it again so that it can interrupt the repetitiveness, or just make the walk cycle much longer.
I kept wondering how you were going to end it, and was pleasantly surprised. I didn't feel like the animation was too long at all or boring, which seems to what others are saying, it just let the focus go to the music and didn't try to compete too much for the attention.
The execution is flawed, but the work as a whole is decent. Work harder on the next project, no more lazy animating.