The subject and concept of this is really great, and I love how we can really follow his emotions through the whole thing- just a great idea for a looping animation all around.
Your technique in dealing with the animation of the fire and water is pretty convincing; the water could be a little less drop like at the top, but otherwise quite nice. I might suggest extending the steaming/smoking bit a little, as it's barely visible (though was a good idea). You could also darken the ground around the fire to show it's wet and fade that out (plenty of frames for it as the girl is walking away).
The texturing in the background here is also pretty good, and I can't complain about your colour choices much. The only thing that really weakens this is that some of the line art in the background is really rough- particularly apparent in the skull and the rocks. You might want to use some references for those. And on the rocks, try making the shadows along the breaks a little more dramatic to show that they're shattered bits of boulders (currently, they look a little like soft round pillows).
Overall, really great job! This tells such a fun little story, which makes it a really charming animation.