New Red Flag Mode

[Zergrush]

Now, I've yet to play it, but I've heard that it's Spartans vs Covenant (which sounds awesome) attempting to protect or kill a prophet. So, before I play it, I just wanted to gather opinions on the mode down as replies, perhaps even explain how it plays, down below. It would also be nice if you could post improvement ideas for the mode down below (James checks occasionally). I'll probably be posting my own opinion once I get the opportunity to play too! 
-generic ending "thanks y'all" or "so guys we did it"