There was an article that Steam and some other company claim it restricts developers somewhat, but I am sure that is something developers will just have to deal with and will find ways around to work with the new Win 8 OS. Windows 8 boasts it's backwards compatibility and so I would expect any current games work on the new Win 8.
An Article Link
I wouldn't believe everything you read though. I think it will be bad for desktops.. great for portable machines, and let's face it.. that's where things are going.
I develop Android apps for that very reason,.. since Microsoft are bringing out metro.. i'll have to learn how to make the best of it. People will work on it and it will kind grow.