Well, the wait is over. Call of Duty: Modern Warfare 2 is finally available, and you probably picked up your copy and started playing. The long-awaited sequel offers both a strong single-player campaign and a huge multiplayer component, complete with advanced perks, weapons and new maps. However, that's not all. There's also Spec Ops, a group of 23 unique missions that you can tackle by yourself or with a friend.

Spec Ops' 23 missions each come with three difficulty settings: Normal, Hardened and Veteran. Each mission has a group of stars to earn, depending on which difficulty you select. The missions come in five groups, starting with the less-than-advanced Alpha and progressing into Bravo, Charlie, Delta and the near impossible Echo.

Alpha

The Alpha missions are not only ideal for getting your feet wet, but also give you a chance to earn enough stars to unlock the next tier, Bravo. You'll begin in The Pit, the same training area where you start the single-player mode. You'll need to clear an obstacle course in the quickest time possible, while shooting cardboard cutouts of terrorists and leaving innocent folks unharmed. Choosing the one-star difficulty lets you do it at your leisure, but to get all three stars, you'll need to clear the course in under 35 seconds. No small task, by any means.

From there, the in-game combat picks up with soldiers that shoot back. Your next stop will be in a wintery air force base, where wave after wave of soldiers come at you, unloading from trucks. This is a perfect mission to become oriented with different types of weapons, including the Predator Drone (a remote-driven plane that can take out groups of enemies with explosives), sniper rifles (perfect for picking off incoming soldiers) and of course, assault rifles. It's best to have both a sniper rifle and an up-close weapon handy, just in case some soldiers slip by. The last thing you'll want is to take damage from behind.

Other missions in the Alpha stage include a sneaky Evasion level, where you'll have to get past sniper rifles and enemy patrols to stay in one piece; O Cristo Redentor, where you'll fight your way through a small village, killing gunmen and avoiding civilian deaths; and Suspension, a full-tilt battle on a partially destroyed bridge, where enemies come at you from both sides. These missions will keep you busy, and even on the lighter difficulty, you'll want to keep your eyes open. Even the smallest mistake (not seeing a soldier come out from behind a car) can lead to a quick death.

You'll need to earn four stars before the Bravo missions are available.

Bravo

Overwatch is a co-op-heavy stage, where one player works against enemy soldiers on the ground while another assaults from the air using the AC-130. If you're fighting from the sky, you'll want to be very careful that you don't put your friend in your sights. Focus on the clusters of enemies trying to close in, and let him or her clear out anyone you miss. (Highly unlikely with the AC-130. That thing packs a punch.)

In the Bravo missions, you'll also find a sensational snowmobile race, where you'll need to avoid rocks, trees and huge drops in order to clear the course in record time. This is even more fun against a friend, who'll try to slow you down or, worse yet, stop you altogether. If you can clear it in 1:10, you'll earn three stars. However, you'll want to practice on the 2:00 setting first, just to make sure you see where everything is.

As for the other missions, they're packed with explosive excitement. Body Count asks you to rack up a high kill count so you can reach at least 30,000 on the scoreboard (and good luck on Veteran difficulty with that); Bomb Squad has you running through the Favela Marketplace, defusing bombs before they go off; and Big Brother requires you to lay waste with a Vulcan minigun, while forces pile up on you. Out of all of these, we love the snowmobile Race. It's too much fun.

You'll need eight stars to acquire the Charlie missions.

Charlie

The Charlie missions are where the difficulty really picks up. From the start of the first mission, Hidden, you'll know you're in over your head, even on Normal. Here, you'll need to evade enemy patrols and sharpshooting ghillie snipers as you explore Chernobyl.

From there, you'll work on your breaching skills in the gulag, the same one you fight your way through in the single player campaign. Breaching and clearing is a fine art, as you'll need to shoot quickly once you set off an explosive. The action slows down for several seconds, giving you a limited amount of time to kill enemies before they can get the jump on you. It's not as easy as it sounds, because debris flies around. Take your time and use your rapid trigger targeting. It's your best friend.

Another snowmobile stage, Time Trial, is available in this tier. This time around, you'll need to hit flag gates in order to keep going. If you run out of time, you fail the mission. Veteran difficulty requires you to start with only eight seconds on the clock, while getting only three seconds from each gate. Considering your run only lasts a couple of minutes (and your friend gives chase), the odds are stacked against you. Learn the course and plan your route accordingly.

Homeland Security is a Horde mode-style stage, where five waves of attackers will come at you with everything they've got. On Normal, they're withstandable, but if you choose Veteran, you're in for a hell of a firefight. Fortunately, along with your ally, you've got access to Rocket Launchers, thermal sighting (to see visible figures from afar), sentry guns and claymores. You'll want to plant the sentries in vital corner positions (where they can hit everything in range) and plant your claymores in the "blank spots". Good luck.

Finally, there's Snatch and Grab, a stage that introduces Juggernauts. These guys are dangerous armor-plated soldiers that are hard to bring down, unless you have something along the lines of a .50 Cal or a Desert Eagle. Avoid them until you're properly equipped. Also be on the lookout for members of Shadow Company; they'll hunt you like wild animals. Grab the Intel and get your butt to the Extraction point as soon as possible.

Earning 20 stars will move you on to the Delta missions.

Delta

Five new challenges await you in this tier, and they're all monsters. Let's start with Wardriving. Along with lazing houses for the Stryker armored vehicle to take down, you'll actually need to go into them, search room by room and shoot soldiers. You'll need to work swiftly in order to achieve the best time possible, especially on Veteran. A few runthroughs on a lighter difficulty wouldn't be a bad idea.

Wreckage gives you a whole mess of vehicles on a bridge to play with. Your goal is to destroy each vehicle, but you'll have plenty of tools to get the job done. C4, grenade launchers, sentry guns and semtex will give you a huge advantage, although they won't necessarily save you. If you have a teammate, have them watch your back and then plant your explosives. If you're on your own, use them sparingly and stay out of harm's way, or you'll have more holes in you than Swiss cheese.

Acceptable Losses gives you a real tough mission, as you'll need to work your way through a remote airbase using only silenced weapons and a heartbeat sensor, which shows you where enemy soldiers are on a grid. If by chance you give yourself away, you'll need to run for cover or stand and fight. Those are risky odds, so do yourself a favor and play it cool. The quieter you are, the better off you'll be.

Terminal also has a monstrous task to overcome. In this stage, you'll encounter several soldiers with riot shields, so shooting them won't necessarily do the trick. Grenades might work, but your best bet is to try and separate them, then melee the enemies real quick (before they can hit you) to throw them off. Once they're vulnerable, knife or shoot them before they pick their shield back up. Just be careful to keep an eye out for surprise attackers.

Finally, there's Estate Takedown, and you will be here a while. An entire estate loaded with dangers must be retaken, and you'll need to deal with more of those ghillie snipers, powerful mercenaries (the kind that don't go down after just one hit) and of course, more Juggernauts. Pace yourself and you might survive. Work out a team strategy, instead of just running and gunning. If you don't, well, you're either an easy sniper target or meat for the Juggernaut to pummel.

You'll need 40 stars in order to access the final three missions. That means you'll need to complete at least a few missions on Veteran, as the Regular difficulty stars won't be enough to unlock them. Oh, and good luck. These final three are the toughest of the bunch.

Echo

If you've somehow made it this far, welcome to the cream of the crop. Here are the three missions that await you:

In Wetwork, you'll need to breach and clear two rooms filled with enemies and hostages. Again, tactical strategy plays a vital role. If you miss even one person, just one, your mission will end due to the death of a hostage. Your best bet is to practice this one several times to memorize enemy positions, and work with your teammate to flank them together. Try to do it one at a time, and...oh forget it. You won't make it.

High Explosive requires you to take on ten Juggernauts, but without the benefit of a Desert Eagle or a more powerful weapon. Instead, you only have a knife and explosives. The knife won't get the job done. You'll need to think this one through. Otherwise, you'll run out of explosives and, yeah, you're done. Remember, just because you successfully kill one doesn't mean your work is over. There are ten.

Finally, there's Armor Piercing, and unless you're a dedicated Modern Warfare player, forget it. You'll need to take on 15 Juggernauts aboard an oil rig. We had our hands full with just ten. Heck, we had our hands full with just two. 15? Work out a plan and wish yourself luck. You are going to need it.

As you can see, Spec Ops has a lot to offer, but it's best suited for those who have played the Modern Warfare games for some time. That's not to say amateur players won't excel, but it'll take a whole lot just to reach the final two levels. And even then, there's no guaranteeing you'll survive unless you're an exceptional player. Don't let that discourage you, however. Grab a friend and unleash hell. Semper fi!