According to Destructoid It looks like Mark of the Ninja is heading to Steam. Developer Klei Entertainment (also the makers of the Shank games) confirms that the game will be available on October 16th for $14.99, and will not involve Games for Windows Live. Remember, this is a Microsoft Studios game so don´t expect it to go to any other home consoles.
Klei Entertainment does confirm that the quality of the Steam port will not be bad.
“I’m not okay in any way with this feeling like a shoddy port” stated lead designer Nels Anderson.
So, if you do not have a Xbox 360 but do have a PC you should really check out this game, it is very fun to play.