It's no surprise that we played most of Call of Duty: Modern Warfare 2 with our mouths open. Activision and Infinity Ward's soon to be critically acclaimed first person shooter unmercifully threw us from one fantastical mission to the next, with painstakingly designed environments crawling with bad guys that possess lightning quick reflexes, expert shooting skills and a nasty habit of throwing multiple grenades at the same time. Snipers lodged bullets into our skulls, hungry canines shredded our throats and explosions quickly removed us from battle. And yet we happily soldiered on, firing numerous weapons (the true stars of the show), rescuing hostages and doing some questionable things in an airport that made us cringe. It's therefore fitting that Modern Warfare 2 appear on cans of Monster "Assault" Energy Drink, since that caffeine powered beverage perfectly fits the game's feverish pace.

Although the single player campaign lasts a short eight hours (or less, depending on the selected difficulty), the designers pull out all the proverbial stops. We barreled through the snowy countryside on a snowmobile, dodging trees and shooting bad guys with an automatic pistol, snaked through a Brazilian city snuffing gang bangers and watched a Russian terrorist kill innocent civilians in an airport. With each passing mission, Infinity Ward never hesitates to put emphasis (however dramatic) on each moment, with slow motion cut scenes, helicopters spiraling out of control and the airport's "departures" billboard suddenly displaying "Flight Delayed" messages. Most of it's over the top, like typical Hollywood action movies, but that's the point. Modern Warfare 2 is more than a simple video game. It's a marvelous fusion of interactive entertainment and film, with a narrative that rivals Ubisoft's Tom Clancy projects. Think Rainbow Six, but speeding along at 250 miles per hour, where instead of only using two or three weapons, your Attention Deficit Disordered soldier moves from an MP5K to an UMP45, a SPAS-12, P90, M9, M240 and a Javelin; those evildoers certainly won't kill themselves.

As for the weapons, there are more than you can possibly imagine, and you'll need to fire them all, similar to how you'd need to drive every single Ferrari in a showroom or "sample" every flavor of ice cream at a buffet. Your love affair with a certain gun (a .44 Magnum or an AK-47) may only last a few trigger squeezes, but much like cars in Forza Motorsport 3 and Gran Turismo 5 Prologue, you'll quickly find several reliables that'll become favorites. Regardless of which you choose, each sounds frighteningly realistic and serves as a grim reminder that these "toys" can turn a human being to jelly (or at the very least, a bloody piece of Swiss cheese) in a matter of seconds. To that we say, kill a few terrorists for us.

We're also happy to report that the game moves exceptionally fast, without the usual trappings that plague unpolished shooters. Not once did we get stuck behind some objects within the environment and need to manually restart a mission, or die because the game lagged. Unless the millions of gamers preparing to hop online wreck havoc on Xbox Live and the PlayStation Network, things move buttery smooth.

That said, we strongly suggest stopping every now and then to marvel at the phenomenal attention to detail. Infinity Ward took things to BioShock proportions, spending time on the most insignificant things within the environments to add that extra layer of realism. Each of the game's vehicles, for example, sport full interiors, whether you can drive them or not. Electric fans hanging on walls work, blowing attached pieces of plastic in the desired direction. Grenades bounce off the ground, then roll as a round object should. These tiny details help separate Modern Warfare 2 from just about every video game that's come before it. Its designers didn't have to go to such lengths to impress us, but they did.

At the same time, that's the game's principal flaw. Most environments and objects are so impressive that the few that aren't unceremoniously remove you from the experience. A tire rolling past is more for dramatic effect than quick physics test, as you'll quickly realize that your soldier not only walks through said tire (without affecting its movement), but cannot fill it full of holes. Meanwhile, a swimming pool was clearly designed for aesthetics, and not for belly flops, as characters merely sink to the bottom without the expected splash or rippling water. Although none of these jarring examples ruin an otherwise stellar experience, they highlight the gap that still exists between movies and video games. Infinity Ward deserves heaps of praise, but still has a long way to go.

Single player is, of course, more of a training ground for Modern Warfare 2's outstanding multiplayer modes, beginning with Spec Ops. A collection of two-person missions (available in both split screen and online co-op) challenge gamers to complete objectives in the quickest time possible. Not only do they provide short bursts of adrenaline, but also provide a look at Infinity Ward's cutting room floor, the missions that almost made it into the story mode. Suspension, for instance, sends you on a point A to point B killing spree along a partially destroyed bridge. Meanwhile, Evasion slows things down and drops you into a snowy woods, where survival instincts and a sniper rifle help you evade and destroy guards and their ravenous attack dogs. In yet another, Bravo, you must protect your partner on the ground using an AC-130 gunship, raining hell from above. Meanwhile, you'll attain stars for successfully completing missions, and these will unlock new ones and hopefully give you a primo spot of real estate on the game's online leaderboards. Even better, each mission comes with three unique difficultly levels that dramatically alter the number of enemies, just in case you need a challenge. Keep in mind, of course, that you can play the majority of these Spec Ops missions by yourself. Regardless, you'll find them both incredibly entertaining and a great way to score a brief Modern Warfare 2 fix.

Gamers with considerably more time, however, will invest plenty of hours in competitive multiplayer. Infinity Ward took what worked in the previous Modern Warfare and added to it, with 16 varied maps spread across multiple types of terrain. One of our favorites, Scrapyard, takes place in an airplane graveyard, while another, Afghan, features a crashed airplane dead center, with small bunkers to take refuge in.

There's more to the game than maps. Most players will flock to the Create a Class option, where they'll select a primary and secondary weapon, along with equipment (throwing knife, blast shield, C4) and grenades (flash, stun, smoke). In addition, Modern Warfare 2 comes with a series of perks, such as Sleight of Hand (faster reloading), Stopping Power (Increased Bullet Damage) and Steady Aim (Increased Hip Fire Accuracy). They'll also gain valuable experience the more they play, and achieve new promotions based on achievements, along with plenty of accolades, like Sharpshooter (Most Headshots), Hard Boiled (Most Pistol Kills) and Revenge (Most Last Stand Kills), among others. Now factor in the ability to create clan tags, select emblems and choose titles, and there's plenty of stuff to mess around with.

With so much attention given to customizing one's soldier, the multiplayer modes are, for the most part, vanilla. Free-For-All is standard deathmatch, and there's Team Deathmatch, Capture the Flag, Sabotage (teams race to destroy a bomb in the center of the map), Domination (capture and hold) and Headquarters (capture the other team's HQ). There's certainly nothing wrong with having these modes, but for such a big budget sequel, we expected a few imaginative ways to play.

Rest assured, though, that your $59.99 (or more, if you splurged on the special edition) is well spent. Call of Duty: Modern Warfare 2 has more than enough guns, modes and "oh-my-god" moments to propel it to the very top of your must have list, with astounding visuals, crystal-clear (and at times, frightening) audio and enough plot twists to make you second guess everything, so gear up, hop onto your snowmobile and haul ass to the nearest store.