I gave this a 3 because it's obvious you put a lot of effort into this game. I think it could work out better if you made the walrus/balloon a little smaller -- it's way too easy to get hit by stuff. The music is awesome though, don't change that haha.
Overall, a fun game but could do with some tweaks here and there. If this is one of your first Flash games, then it's a fantastic start for sure.