Officially old saves won't work with GFWL-less Batman, but unofficially people have been tinkering to get them working. This patch arrives with a 75% off weekend sale.
Those who purchased the standard version of Batman: Arkham City and purchased the Harley Quinn DLC might have noticed they've got the GOTY edition in their library.
With the demise of GFWL, the Harley Quinn DLC wouldn't have been accessible because it required having the Games for Windows Marketplace to download the content, despite if it was bought through Steam. The GOTY edition includes the DLC as part of the full download however, hence the free upgrade.
How does one attempt to salvage Batman: Arkham saves held hostage by GFWL?to find out.
Right now Batman: Arkham Asylum and Arkham City arefor the weekend. Those with retail keys are also reportedly able to activate them through Steam, although there appears to be some teething trouble with them.