Here's a new interview for Mass Effect with Ray Muzyka (co-founder of Bioware), among the things that stood out were the game's length and that they're working/planning on future downloadable content for the game.
http://www.xbox.com/en-US/games/m/masseffect/20070917-raymuzykainterview.htm
How Long
It's safe to say Mass Effect will stand proudly among the longest, most expansive games yet available on Xbox 360™. But exactly how long and how expansive is the experience? Here's what Ray had to say:
"It took me about thirty to forty hours to do just the core story, and another twenty, thirty hours of uncharted worlds beyond that. I think most players will probably spend forty to sixty hours, somewhere in there … this is a big game. It's all at the same production value too. It's all consistent high-quality. I'm amazed, the team has done an amazing job."
Extending Mass Effect
Not since The Elder Scrolls® IV: Oblivion™ has a game been so perfectly suited for post-release content. With literally an entire galaxy to explore, the possibilities are endless. I asked Ray if they were looking to release downloadable content via Xbox LIVE® Marketplace:
"Yes, yes, we are. We are doing digital distribution and post-release content. We haven't revealed what we're doing yet … we are going to build something for sure. We're just not sure about the details yet."