The backgrounds were amazing.
Probably one of my favorite parts of this. The animation could not be any smoother, and it shows that you have skill with gradients. The writing was miminal, but it was there, and satisfyingly got a point across as well. I didn't really like the character design of Nim. He was animated well and all, I just didn't like how he looked. I am amazed, though, that I haven't watched this until now. Overall, it's evident that you have reached your goal: relying heavily on mood and atmosphere to bring the story more to life.
This also brought to mind about how really well animated movies like this end up. A lot of people might say that these movies have no storyline. Storylines don't have to have dialogue in them. Simple body language sometimes tell the story better than any talking at all. This, There She Is!!!, and the Brackenwood series all face this problem. Loaded with good graphics to get strong body language into the story when some are too dense or stubborn to motice how important it actually is. Then those people have to go ranting on about how there's absolutely no storyline and that it's just crappy eye candy.
I'm done ranting myself, now. Good job on making this flash, I hope to see more of your work!