Requiem Safe Spot
On the final level Requiem -- where you have to wake up and kill all witnesses in the church -- there is a major glitch. As soon as you wake up, exit the church and head south. There will be two stone mausoleums (or sheds). Enter the one that is furthest away from you. When the doors are closed, the guards cannot open them, and they will all come running down. You can keep opening and closing the doors as you please without worrying about all the guards rushing in to kill you.