A good start to the Black Ops series, only held back by the poor campaign.
Campaign
To be fair with Treyarch, they tried. Black Ops became the first game in the Call of Duty series to be set in the Cold War. Black Ops follows the story of a special forces operative, Alex Mason, as they fight to prevent a chemical weapon known as 'Nova-6'. Mason is joined by various other main characters in the campaign, such as CIA agent Jason Hudson and fellow special forces operative Frank Woods. Gary Oldman also reprises his role as Viktor Reznov, a main character from World At War.
The idea for the plot is solid, but the reality of it isn't. The storyline is often confusing; the numbers station is only fully-explained when the player is too far into the story. It also appears at times that Friedrich Steiner, right-hand man of antagonist Nikita Dragovich, is the main villain in the story. For a main antagonist in a Call of Duty game, Dragovich rarely makes an appearance. This is disappointing as it means that players never seem to be fully-immersed in the storyline.
The ending of the campaign is also a disappointment. I always try to keep major spoilers out of reviews so it's relatively hard to explain why the ending is so poor, but it feels like the whole campaign is rather dragged-out, and could have easily been explained in six or seven missions. As a result, some missions, such as Executive Order, S.O.G. and especially The Defector, seem like they were just developed in order to pad out the campaign, as they serve little or no importance to the campaign story.
The last negative point I'll mention in the Black Ops campaign is infinite enemies. I'm not quite sure what was going through Treyarch's heads when they chose to include infinite enemies at certain points during the campaign but I'm fairly sure it was some form of an illegal substance. Notable points where this occurs is during the hallway scene in Executive Order and the barrel scene in S.O.G. Enemies will indefinitely spawn and engage the player until the player either goes a certain way or performs a certain action. I'm all for developers trying to challenge gamers, but infinite enemies creates confusion. One gamer told me how he fought the hallway scene in Executive Order for 20 minutes before searching the internet for help. A quick internet search for "Executive Order hallway veteran" reveals he's not the only gamer to have this problem; one player comments how it made him want to "throw his controller through a wall". Perhaps the most frustrating thing is that Treyarch could have easily made infinite enemies a lot less confusing with NPC speech giving hints to the player, i.e. "we're gonna have to find another way around".
Online Multiplayer
Now that the negativity is out of the way, it's time to mention Black Ops' saving graces, the online multiplayer and zombies game modes. The actual online multiplayer gameplay hasn't changed a great deal from Modern Warfare and Modern Warfare 2 (but hey, don't fix what isn't broken). What Treyarch have done with the multiplayer is focus on customisation, introducing what they call 'Create-A-Class 2.0". Weapons can now be camouflaged much more extensively than in previous titles, with writing and emblems as well as the already-established attachments and camouflages. For the first time ever weapon reticules can also be modified, face-paints can be unlocked and there are new customisable killstreak rewards, such as explosive remote-controlled cars and attack helicopters that can be controlled by the player.
For the first time in the series a currency system, known as 'COD Points', has been introduced. Players can spend their COD Points to buy weapons, accessories etc. Contracts can be purchased, which allow players to earn more COD Points by completing challenges in the set time period. A multiplayer mode called 'Wager Matches' has been introduced, which allows players to gamble their COD Points.
The online multiplayer did attract some criticism, however, when it was revealed the game wouldn't have dedicated servers; a feature that was present in Modern Warfare 2. Servers are instead provided by Game Servers.
Zombies
The innovative zombies game mode makes its return in Black Ops, and it's been revamped. The original characters from the World At War return in Black Ops, and the original World At War zombies maps have returned in the Rezurrection map pack.