Better to buy it from Steam directly ....

The Batman Arkham City game formerly activated on the Games for Windows Live platform (GWFL) is not either on Steam, the latter now hosting the game on their own platform (Microsoft has closed so far the GFWL). The purchased game (in destocking games) includes a license key with 25 characters, not the one who is only 12 and pensionable accepted on Steam. You can easily check this info on Steam. This key is not activated and no 2 platforms even logged in or GFWL Steam account. The game installs on Windows Seven 64 bits but I find myself unable to play because activation is rejected in all cases. Of course the players who bought this version on Steam are now oriented GOTY Version (game of the year) ... only activated at Steam. By cons games purchased in retail with CD keys (in my case) are now at an impasse. As said in the title of this opinion, it is better to buy directly from Steam, you'll be sure to at least be able to activate and above all, play ...!
Some sellers seem unaware (or unscrupulous!) And did not hesitate to sell licenses unusable.
So beware if you plan to buy other Batman game or other former GFWL.
Amazon is not liable in this case but must remain vigilant on the equivalence of products when these are offered by several vendors. I opened a claim and hope reimbursement should happen naturally (well, hopefully).
Too bad because the game was promising ...