Why are you posting here? now? go out and play the game fool!
I love it, the skull system is back, and now you have a choice of when and where to activate the skulls, there is a new aspect to single player, its the metagames on every level, basically everything can have a point value, such as: kill hunter, or kill teammate (neg points). And well you strive to get a certain ammt of points and its quite fantastic, oh and 360 achievements are always fun.
The forge is a do all map editor that you can play either after you create the map or during.
Basically you switch between spartan and guilty spark, as guilty spark you can't attack but you can summon stuff such as vehicles and weapons and teleporters, then instantly switch into spartan and use what you made. So, you need a rocket to take down that banshee, no prob, press d-pad up, x, spawn a rocket launcher, and take down the banshee.
There are new game modes, (and the old are back) so: slayer, Oddball, CTF, Assault, juggernaut king of the hill, territories, are all the nice old ones, then I think VIP is new (kill the vip for points, vip has overshield, 1 vip per team), and infection (my fav) Each player starts either a zombie or a human, with both species having very different attributes. Zombies score by killing humans humans score by killing zombies any human killed by zombie becomes zombie.
Single player is nice...just great.
Graphics: MY EYES ESPLODED
Sound: it's like listening to a symphony of dying grunts, (that occasionally yell after you kill a fellow grunt: He was my nipple buddy).
Story: 10/10 no spoilers sorry.
Co-Op, split screen: 2nd player is part of the story and is in the cinimatics

X-Box Live: 4 player (other 2 players also incorporated into story nicely)
SO did I get my moneys worth?
HELLS YEAH
Will I get fat and get carpel tunnel
HELLS YEAH
should you get it?
I'll leave it up to you