An interview on the Bioware blog has revealed a few more crumbs about Mass Effect 3's co-op mode, talking about how succeeding in multiplayer mode will have an effect on the single player campaign.
Bioware say that singleplayer "can still be played all by itself without any kind of multiplayer or third party and you can still get the absolute best ending. This just gives you new options to be able to get that ending."
In singleplayer, the Galaxy at War System measures how well prepared the universe is for the imminent Reaper invasion. Your actions in Mass Effect 3, and decisions made in Mass Effect and Mass Effect 2 will boost this level of preparedness, altering how the trilogy's finale pans out. Gaining experience and achievements in multiplayer will also boost this score.
The co-op mode also means a few brand new team mates. Bioware confirm Krogan, Drell and Asari characters, but also say that "there will be a lot of interesting races that you may not expect to be able to play as because they wouldn't normally be looked upon as characters who are for the fight." As ever, we're secretly hoping for a playable Elcor, or a heavily armoured battle-Volus.
The new characters won't appear in the single player campaign, however. "While it is separate to the main story they will never be involved in the actual campaign of the main story. It's more like a side mission to the SP," say Bioware. "We don't want to create situations where MP players have something that SP players couldn't otherwise see."
The multiplayer items will be "very similar on the weapons side" to singleplayer, but "there are more customization options for the MP armor side"
"They are structured differently so stats don't play the same way, so SP guys have something that feels better for SP and MP guys have something that feels better for MP."
The multiplayer mode is new territory for the Mass Effect series. Beta tests are slated for January and early access will be granted to those who bought Battlefield 3 new. Are you interested in the co-op mode, or will you be sticking to singleplayer?