The aim of the mission is to fight your way through enemy militia while gaining stars in order to unlock new levels, with harder difficulties awarding more levels. Spec Ops is also offered in the difficulties of Normal, Hardened and Veteran with the amount of enemies rising and the civilian death allowance lessening with each difficulty. Another similarity that Spec Ops has with Nazi Zombies is that players are automatically given the last stand perk, allowing their partner time to revive them. Word has it that Last Stand will now also allow you to drag yourself around somewhat; a little like Gears Of War I would imagine, but a lot more awesome.
Since its announcement Spec Ops has become one of the most anticipated areas of game play in Modern Warfare 2 and I have no doubt in my mind that it will surpass everyone's expectations.