originally posted by BladeBlunter
There is what I believe to be a beta patch doing the rounds, there's mention of it on the Steam Forums and if any one needs it I can upload it if necessary. I was stuck in exactly the same place, no way back, no way forward.
So I downloaded this patch (after careful AV and malware scanning) extracted it to see what was changed, backed up the original files then patched away.
No issues with starting, or getting into GFWL, and lo & behold, not only did run smoother (DX9) but I could also play under DX11 without crashing or stuttering, and though the lock to to the tower was showing red, I could still use the cryptoscanner and open the door. It worked wherever I saw a Tyger locked door. I went back outside after the next phase but before I went to the finale and I was able to open previously locked doors for trophies etc. and everything worked great.
I don't normally contemplate patches of this sort but after all this time I'd invested in this game I wasn't going to be beaten so I hope it works for anyone who wants to try it, I'm glad I did