Biggest Bang Achievement Glitch... HELP!!!

[Doodle]

So I started a brand new game on hard difficulty in Arkham Asylum now that GFWL is finally gone. Every achievement has worked thus far until I finally beat the game this evening. No achievment popped and now I can't go back to replay the final fight.

Does anyone have any solutions or ideas to fix this glitched achievement for me? Playing this game on hard mode was not too difficult but I sure as hell do not want to go back and replay the game just for that last achievement.

Please help!

[stewarthoppy42]

Hey man, I've got the same problem as you. Did you ever get round it or have to give up?