Summary: I bought this game and added it to my Steam games. I had a real painful time trying to making to work since Games for Windows Live does not seem to work on Windows 8.1, or I am frankly so useless that I could not install that thing and make it to recognize me and let me play this game.
Summary: First let me start off by saying, Dark Souls is the best game ever made for PS3 or Xbox360. The reason I am telling you not to buy this because it is a total waste of money because the designers NEVER finished formatting the game for PC... it is unplayable, the game itself is still 100% still an Xbox game and they intend for you to play it on PC. Please listen to my warning and don't waste 40$ on it like I did.
Conclusion: In effect the game is excellent - if i could play it. This version basically is a packaged brick. Windows live games isn't supported and there's well known issues getting this game to work on different pc types. Bottom line my advice - buy it from steam and hope it works - at least there you can get support from the supplier. Namco are great, excellent support - microsoft are rubbish and don't contact you. It's not worth the risk.