Call of Duty 4: Modern Warfare may have sent jaws to the floor during E3 with its tense single-player levels in realistic war zones, but the multiplayer was mostly a no-show. However, after getting a lengthy hands-on with the game's player-on-player action, we can say that it's just as impressive as CoD4's cinematic campaign - and addictive as all hell, to boot.

Granted, our short time with CoD4's multiplayer only showed us one game type - team deathmatch - and the game seems pretty sparse at first, with just three soldier types to choose from: Assault, your standard M16-equipped grunt; Special Ops, who carry a more compact MP-5 submachine gun and can stick remote-detonated C4 charges to things; and Heavy Gunner, for those players who like to move slowly and carry a big machinegun. But that's just for starters, and the game is packed to the gills with cool incentives to keep you playing. Start racking up kills, and your rank will shoot up quickly, unlocking everything the game has to offer as it rises.

First, new classes open up - we unlocked the Sniper and RPG-toting Demolitions specialist after our first few rounds. After that, though, you'll earn the right to create your own classes, and that's where the real depth starts. It begins with picking your own weapons - maybe you want to carry an MP5 and a rocket launcher, or a sniper rifle and smoke grenades - but that's really the least of it, and you'll be able to unlock tons of tinkering options the more you play. Weapons accessories like grenade-launcher attachments, laser sights and silencers can all be earned and added, and if you complete certain challenges with different weapons - scoring 25 kills with the MP5, for example, or as many headshots with an AK-47 - you'll earn special modifications like weapon camouflage, enabling you to announce your badassery to anyone who crosses your path.

Your weapons aren't the only things you can tinker with, either, and you'll gradually unlock Perks to give you an edge in battle. These come in three distinct categories, and you'll be able to pick one Perk from each. First, there are weapon Perks, which enable you to carry more C4, grenades or rockets than usual. The second and third categories boost your soldier's abilities and change the way he interacts with the world, including increased stopping power, extra health, the ability to shoot through walls and the ability to pull the pin on one of your grenades as you die, effectively discouraging other players from lingering over your corpse.