Good for your first animation. As you can see for yourself though, the animation is very crude. Your should try watching Madness Combat animations at slowspeed(on youtube for instance) and try to copy them and get a grasp of the physics and movement. There are also some nice tutorials in youtube to get you started(Green Pepper Studios e.g).

+ for the music also.

I enjoyed watching this very much. All four of you made superb animation. The fights were fun to watch too and I feel the music was fitting. Those masks wearing characters could very well be part of a story. You should try to make something around that because the concept looked interesting.

Like the art style, voice acting and the lip sync but the animation could use a little work. It was also short in length.