Really freakin' awesome
It looks amazing. If it's supposed to be an animated series, try to make it not so two-dimensional and side-scrolling-platformer-y. That's the only problem I had with it; it looked too much like a trailer for a 2D Flash game and not enough like an animated series. If it is a game, that's cool, too, but it looked... too much like an animated series, in that there weren't really very many characters (enemies). If it is a game, shadow-y monster people could be cool enemies, but you only showed them for about two seconds in the entire thing, which is what makes me think that this is an animated series and not a game.
tl;dr-If you're making this a series, make it more 3D-looking. If you're making a game, make a trailer showing more than just four characters.
If you did the 2D-looking animation because of time restraints, I can understand that. It looks awesome regardless of what I say. XP