What you are about to see in this video are aliens under attack by bugs. As three aliens get captured by the bugs, other aliens try to fight back and survive.
Positives: Excellent variety of camera angles. You tried some interesting thing with the actions. The sand tunneling centipede was very effective. The lighting helps to create an eerie mood.
Improvements: I made this comment on part 2, but it applies here as well. Try creating your characters out of clay or some material that will allow you to articulate the limbs. It would be great to see the legs animate individually. Use more inbetweens. This will make your animation smoother.
Positives: Very good character motions. Good use of backgrounds for the characters to interact with.
Improvements: A higher frame rate would have made the action move faster, and make the motions more believable. Why have it in two parts?
Positives: Generally good speed throughout. Nice use of a variety of materials. I liked having the one creature go under the sand and move that way.
Improvements: Some portions could have been shot a bit closer. When moving a cast of so many characters, be a bit more random in movement so that each character doesn't move exactly the same.