There is an entire subset of the Call of Duty fanbase - arguably the largest subset - that could not possibly care less about the singleplayer campaign and just wants to spend time shooting other people in the face online. Our Editor-in-Chief Russ Pitts had some harsh words to say about the campaign in Call of Duty: Black Ops, noting that while the game had flashes of momentary fun, it kept on getting in its own way. Thankfully, there are no such obstacles lurking in the multiplayer portion of the game. In fact, it might be accurate to say that the multiplayer could well be the series' best.
Treyarch knows that Call of Duty fans have very specific expectations about their multiplayer, and the core backbone of the online gunplay hasn't really changed from previous games in the series - why tamper with a formula that has proven itself so wildly successful? Black Ops multiplayer is still a breathtakingly fast-paced effort that revolves around aiming down iron sights, gunning down your enemies in short bursts, and quickly respawning upon death to do it all over again. All the necessary pieces are in place to make fans of the series feel comfortable with diving right in headfirst; Treyarch doesn't rock this boat unnecessarily.
The developer makes one crucial change that seems small at first, but winds up feeling pretty significant. As in previous COD games, you unlock new weaponry and equipment for your character as you level up (by shooting other people in the face), which gives players the opportunity to customize their characters to fit their playstyle of choice. Black Ops spins this tried-and-true concept around and ties the whole thing to a currency system: As you play the game, you accrue credits in the form of "COD Points," and you can't equip a weapon, weapon modification, or gadget until you've spent your cold hard not-quite-cash.
To some, this might sound like an unnecessary second hurdle on the road to having a character that's fully kitted out in every way. In practice, it lets players customize their classes at their own pace, buying the things that they find most appealing first and saving the rest for later. Most importantly, however, it encourages players to take advantage of the various methods Treyarch offers to get rich quick.
In Black Ops, you can purchase Contracts that effectively function as little miniature achievements, asking you to accomplish a certain task in-game. It can be something as simple as "win a round of Team Deathmatch," or it can be something more difficult like "get five headshots with (Gun X) without dying." Complete your Contract and you get a bonus payout - the riskier or more complicated the Contract, the bigger the payout - but if you fail to succeed within the time limit (that is, time spent alive in a match), you're out the money you spent on the Contract in the first place. Watching those last few minutes on your Contract tick down as you try frantically to get the kill streak you need is a tension and sense of urgency that just hasn't been there in previous games in the series.
There's also an entire gameplay mode dedicated to putting your money where your mouth is. In Wager Matches, every single round requires a buy-in that can range from the marginal to the exorbitant (depending on your risk tolerance and confidence). Prevail, and you'll get your money back and then some. Lose, and you're that much further from your shiny new gun.