Call of Duty: Black Ops
is a very elemental first person shooter. There's no real frills here. Collect weapons and scavenge for ammo as you go, and take down pretty much every enemy you meet in order to survive. The now standard health recovery system is in place here as well - if you need to recover health, you can simply sit in cover for a little while and you'll be fine. You'll travel through secret bunkers, escape from prison, pretty standard action fare.
It's hard to associate this game with its big console cousins because it just is so simple. You're told to complete missions and rescue operatives, but you're really not given a deep story beyond this. It seems you're expected to get this from the "full game" on the consoles. You're told that you need to complete the mission, rescue the "operative," but that's about it. You're really not given much in the way of context or detail about what you're doing and why. That's just a little disappointing, especially if this is the only version of the game you're going to buy. Yeah, you're not really buying this game for the story, but hey, this is a series that has built up some of the biggest plot twists, the biggest shockers we've ever seen.
Beyond the campaign mode, you've got a couple different Single or Multiplayer modes. Within the regular Multiplayer, you've got several game modes you can go into like Death Match, Capture the Flag, and Sabotage (a defend the target from the other team game). There's also the famed Zombie mode, which is available in Multiplayer and Single player modes. It's just what it sounds like: you must survive against a slow moving, but numerous horde of zombies.
On the single player side, there's several Challenge modes, but unfortunately these are pretty much rehashed versions of the Campaign mode. Arcade mode adds a timer, another mode adds a specific number of kills to obtain, etc. There's also an extended Training mode that has you take down pop-up targets. It's called Killhouse. It's a pretty over-dramatic title for this kind of thing, for sure.