Visible crew/equipment: When the police cars arrive after Strahm's cube trap, there is a very quick shot of the black police car passing before the camera. When it does, a white screen and black stage light are reflected on its surface. This is just before it shows the SWAT going in. (00:10:45)Ssiscool
Continuity mistake: Spoiler: Right at the end, we find out that Saw III and Saw IV were happening simultaneously, as demonstrated by Strahm walking in and killing Jeff. We then see Hoffman close the door on Strahm, locking him in the room. Saw V continues from the exact moment when Hoffman shuts the door on Strahm. In Saw V, Strahm quickly kicks the door with his foot just seconds after Hoffman has closed it. However in Saw IV, we see Hoffman walking away. In this shot we should hear Strahm kicking on the door.Ssiscool
Revealing mistake: When Strahm is being crushed by the "closing walls" at the end, watch closely during the last few seconds. There is a brief shot from above Strahm, looking down as he screams and the camera is spinning. If you watch closely, you can tell the "closing walls" that are crushing him aren't moving during this shot.
Continuity mistake: Jigsaw puts the razor down on a piece of paper and it is in a near right angle. When Hoffman picks the razor up, it is still at an angle. However, as soon as it's in his hand it's perfectly straight. There is no time for Hoffman to straighten the razor without us seeing him do so. (00:47:00)Ssiscool
Continuity mistake: When the five victims are in collars ready to start their first test, Ashley gets decapitated at the end. There is a shot of her head on the ground in a pool of blood. But in another scene later on Mallick goes through the door into the next room where you can see the head on the ground, and the pool of blood under the head has vanished. (00:26:50 - 00:33:15)travisty847