Microsoft will be offering full retail games like Assassin's Creed and Mass Effect as downloadable games via Xbox Live Marketplace Games On Demand starting this August. They'll boot straight from your hard drive, just like installable games.
That's all great. But some games don't quite work as intended when played from the hard drive. Games like Grand Theft Auto IV and Halo 3 don't perform up to par, because they were designed to be streamed from a DVD. And Microsoft may be addressing that problem when it launches Games On Demand.
Microsoft reps said that any game planned for a Games On Demand will go through a "rigorous" QA process to make sure they work precisely as intended when played from a hard drive.
And mega blockbusters like Halo 3 and GTA IV may need to be "fixed" to become a Games On Demand, something Microsoft seems willing to do.
Oh and one other thing. Those Xbox 360 games you can buy as Games On Demand downloads will be available for purchase via the Web Marketplace, but not through Amazon.com.