Pretty good!
For a relatively new animator, it wasn't half bad. What you need to work on though, is having a way to identify your characters with something other than colour. It was a little confusing how blue stick-men were on the red team, so maybe give them wristbands to signify which one they're on. Even better, do that, but also change the names of the teams so it's easier to tell people apart.
The sound was pretty good, and timed quite well. If you want to take the next step up, use some form of voice acting. Again, a good way to distinguish your characters. One problem was that if you used scene select, the music wouldn't start.
Bonus points for using the CaveStory theme. I hope to see more of you in the future. :)