This seems like it can be an interesting story. You show a character not like other superheroes, as he seems like a coward! Sounds like a funny series you are going to make. The drawings were good, nice coloring and decent animations too. I'll look for the first episode when it comes out.
This is a little short for a trailer, I think. It's very short, especially for the filesize. You definitely need to learn how to compress audio, or you will never be allowed to upload a full episode without it.