Okay, played it for about an hour, have some pros and cons:
Pros:
-Guns are awesome
-Effects are cool
-Swords/melee combat is awesome
-you can deflect gun shots with melee
-adrenaline makes you or breaks you
-Alot of fun
Cons:
-Guns always beat melee unless your up close
-Freeze attack from anubis is overpowered
-some melee attacks are just useless (i.e. when your the big green guy and jump and press B, thatdoes nothing but get you to the guy but by the time you can focus, he either kills you or is far away)
-its hard to catch up to people and that makes it hard to sneak up on people and melee attack them.
On a side note, the levels aren't the best (there are 3 intotal) but are good, online play only has 4 (a bit dissapointing) but the full has 8.
The demo so far gets a 9.6 out of 10 but I would prob give it an 8.5 if I wasn't looking for something other than halo 2 to play.