(at around 18 mins) When Jigsaw is explaining Daniel's situation to Eric, the clock on the wall says 7:30. After the timer in the monitor room has gone down by 90 minutes (at around 59 mins), a shot of the wall clock shows the time as 8:00 - only half an hour later.
(at around 1h 11 mins) The first time we see the number 9 on Addison's neck, it has a curvy line, looking like an upside-down 6. Later, when there are flashes of the previous numbers (at around 1h 21 mins), the 9 shows up with a straight line.
(at around 14 mins) When the SWAT team have their guns aimed at Jigsaw's heart (just after Matthews says "Hey - is this close enough?", we can see three laser guides on his chest. Then one of the SWAT team members points his gun down, but there are still three laser guides on Jigsaw's heart. Seconds later there are two lasers, then three again.
Rigg's earpiece disappears between shots.
(at around 35 mins) Laura enters the room with a clean nose; in the next shot, she has blood running from her right nostril. In the following shot, it has disappeared.
(at around 12 mins) A SWAT member uses a battering ram to open the outside door of the facility, but the door opens outwards.
(at around 24 mins) To fire a revolver, the hammer must fall forward to drive the firing pin into the cartridge's primer. When the key is turned in the door, we see the booby trap mechanism begin to cock the hammer of the revolver. But just as the hammer reaches its full rearward position, and before it falls forward, the revolver fires. Then the hammer falls forward.
In the end, the credits for Xavier/Franky G and Addison/Emmanuelle Vaugier are misaligned.
(at around 12 mins) The crew is reflected in one of the large white SWAT vans that pulls up outside the steel factory.
(at around 9 mins) The message written on the ceiling ("Look closer, Detective Mathews") misspells Eric Matthews' surname.