Hands-on previews of Mass Effect 3's multiplayer offering have begun to crop up around the web, providing details on character customization, gameplay, and precisely how the mode will affect the single-player campaign.

As anticipated, Mass Effect 3's four-player co-op takes after Gears of War's popular Horde mode, pitting your team against waves of increasingly difficult enemies. The exact lineup of foes will vary based on map, but you can expect to fight your way through many of the game's iconic baddies, including Cerberus, the Collectors, and those oh-so-cuddly rachni. Combat will be broken up with special objectives the team has to accomplish, like defending an area or disabling enemy hardware.

Of course, no one wants to be on a team of four Commander Shepards, so co-op will feature an entirely distinct line-up of user-created characters. While you'll be able to pick from any of the game's humanoid races — Asari, Turian, Krogan, Salarian, Drell, and human — the impact of your selection will only be a cosmetic one. The real meat of customization comes from your class, which affects your special abilities and firearm proficienies, although you'll be free to equip any weapon you like, regardless of class. As you play, you'll earn experience points and money that let you level your character's abilities and buy and upgrade weapons.

Perhaps most enticing of all is confirmation that Mass Effect 3's multiplayer will have an impact on single-player. Once your character has reached a certain level, you'll be given the option of exporting him or her to the Galaxy at War map, giving Commander Shepard a powerful new unit to help hold off the Reaper invasion. Additionally, putting time into multiplayer will help raise the galaxy's readiness level, a stat that helps determine the outcome of the game's story.

If online play isn't your thing, though, there's no need to worry you'll be missing out. There will be plenty of other ways to raise your readiness level and nab the best ending, and you can even hop into multiplayer matches solo should you so desire.

Mass Effect 3 is slated for release on the Xbox 360, PlayStation 3, and PC March 6 in North America and March 9 in Europe.