I've just found a game breaking glitch on Defiance and just wanted to give other people a heads up so they can avoid it.

It's on the Vorador's Mansion level with Raziel. Right at the beginning you have to fight a few statues and upon killing them a window is cracked so you can gain entrance to the mansion. After you've smashed it open in the material realm It's supposed to act like one of the metal grates that you can only get through in the spectral realm. However, I ran straight through it in the material realm, which is apparently not what you're supposed to do.

The level runs completely normally until you've obtained the Heart Seeker spear, at which point you're supposed to get back into the mansion the way you got into it the first time (via the window), as you are unable to get back the way you came due to a grate being very high up. However, if you do what I did you find that you are unable to get through the window in the material realm, and you are only able to access the entrance corridor in the specral realm before being stopped by a sealed door. This means there's no way to get back into the big fountain room, which means that you are completely unable to progress.

I really don't have the patience to play the game from the beginning so i'm giving up, but I hope this might help someone else avoid this problem.