Not too bad
Overall, I can tell that you put a lot of work into the animation, and it turned out pretty good, but I have some advice.
1) Subtle animations, like a head moving while talking, or using a blur in certain situations, really makes an animation come to life. Making the characters move more while they are talking, having a sunset in the desert, really small, unnoticeable things make the animation a lot better overall. You should try to involve those more in your animations.
2) Since the majority of the animation was audio-heavy, you should have made the voicing more energetic, and which have more variety. Also, the microphone quality was fairly bad. I would suggest getting voice actors for something like this, there are plenty of places to find them on the internet for free.
3) Try not to use shape tweens. They look very cheesy.
Other than that it was some pretty good animation with a good lesson behind it. Good job! :)