With the removal of Games for Windows Live many people lost their Batman savegame data. Why they didn't automate this process is beyond me. So I, like many others, was left searching for a way to recover what I had done with the game.
This guide worked well for me, but with the Arkham City gamesave edit I had to search for the second 00 00 00 03 00 and remove all the data before it. I also used the HxD Hex Editor instead of what they recommended in the guide.
MAKE BACKUPS!
Tips
Don't mix patched with unpatched savefiles or the game could crash.
I'm using Hex Workshop but her