A Very fun game to play with friends, and has hours upon hours of replayability!
Campaign: Black Ops has a solid campaign mode, with lots of action packed cinematics and battles. There is lots of different characters that you will meet throughout the campaign, and each one has a big part in it, so no pointless characters which only appear once. Once you complete campaign, there are still 42 intels maximum to find, and more than half of the game's trophies are achievable only in this mode, so replayability is strong if you are going for platinum.
Multi-Player: The Reason why CoD is what it is today! You have all of the regular stuff, and lots, lots more has been added. This will be the mode that reels you into Black Ops, and has lots of different game modes. There is a store in-game in which you can buy guns, perks, symbols, and a hell of a lot more with CoD points you earn. As you rank up, you will have access to buy stuff from the store that you couldn't at previous levels. There aren't many Multi-Player based trophies to obtain, but that won't stop it getting boring
Zombies: The Zombie mode from World at War is back, as is all of the fun, addicting hours of Co-Op zombie-mashing gameplay. 2 Maps are available with an original disc of Black Ops, Kino der Toten(Theatre of the Dead) and"Five". Both have tons of weapons to use, some are only available to Zombie mode, and every gun has an exclusive upgrade thanks to the Pack-a-Punch machine. Personally, this is my favourite mode. I would pay the original price of Black Ops just for this mode, so it must be good! ;)
Overall comment: It's a very good FPS game, if not one of the best. It has a decent amount of content, a more than great amount of hours of replayability, and over 7 mllion players playing it as we speak! It only gets a 9.0 from me because the online mode has already got a few hackers in it, and, just like every other CoD game, each map pack will be released onto Xbox 360 a month earlier than PS3 due to Microsoft having a contract with Treyarch