Gears 3 story, map and co-op DLC planned
MS expects 4m to play by end of week.
Gargantuan Xbox 360 exclusive Gears of War 3 launches today, and developer Epic Games has promised to release substantial downloadable content.
Epic will, post launch, be "constantly" working on title updates for the shooter. The team released six for Gears of War 2.
Epic is also working on downloadable content, including new maps and new "co-operative experiences".
In an interview with The Telegraph, Epic design director Cliff Bleszinski confirmed that Gears of War 3 campaign DLC is also planned.
It will not, however, feature series stars Marcus and Dom.
"One thing I can tell you is that you're not going to see Marcus or Dom or Cole in it," he said.
"I believe that DLC should be unique and cool, like Lost and the Damned, Gay Tony, Mad Moxie's Underdome Riot. All those kind of things. DLC's the place where you play and have fun. So that's one thing that's an indication of where things may be going in the future."
Microsoft sells a 2400 Point Gears of War 3 Season Pass, which grants buyers a 33 per cent discount on the first four DLC packs.
Meanwhile, Guy Welch, a Microsoft senior product manager, said he expects more than four million will be playing Gears of War 3 by the end of the week. 75 per cent of those, Microsoft reckons, will play the cooperative and multiplayer modes on Xbox Live.