I did this for 3 weeks
I don't want to seem like an asshole, so please take this with a grain of salt from one aspiring 3d artist to another.
It visually looks like it took only 3 weeks. From what I've heard in talking with people in the industry a demo reel needs to be polished to the max. So they say simplicity is the key.
While I love your idea, and the flow I think that it is being put off by the visual appeal.
As far as specifics which I think may be useful and or helpful.
The particle details are a little strange looking. Their interactions with the scene look akward.
The roof in the opening scene looks great along with the moon.
Your first character looks very good overall. The face doesn't look like it suits the environment or the body.
Both characters movement is very well done, however the arm and hand motions seem a little lack-lustre in comparison.
The sketches and their display is awesome as well. I think if you created one character as detailed and polished as the drawings you would be well on your way to getting into the field.
Overall I'd say you've got a great base to work off of but that you tried to do too much in too little time.
Keep up the good work!