First of all, don't beat yourself up over an online (thereby worldwide) competition when you reach a single digit place!!! That's still G-DAMN respectible!
Now, someone suggested an operation of suggestions, and I'm the kind of guy who likes criticism as long as it's CONSTRUCTIVE. (Okay, I'll use the indoor letters now...lol)
You have a fine animation going, and I understand the theme is based on the Halo game. However, you might consider, even as a tribute, that you take the inspiration from the game to develop a whole storyline of your own, and then tell it. It's not about getting greater creativity on characters or bigger FX, or even more detail. You already have all of that. Just develop a little more complete story to tell and tell it, start to finish... even if you get close to finish and fade out to let the audience make their own conclusions. (okay, sounds cheap, but it is effective on most judgmental type people...) It has been known as one of my favorite ploys.
Otherwise, yep... sticks... fun... Me likey!