Factual error: Mary Jane said, "I spent seven days in a pitch-black shipping container with no food or water and nine other girls." A human can go 2-3 days without water, but not 7. (00:37:18)
Revealing mistake: During the struggle in the elevator, the pistol discharged three times into the ceiling (covered light) but no fragments fell. A little later when the whole ceiling is shown, the ceiling is not damaged and there aren't any signs of bullet holes. (01:04:35 - 01:05:12)
Revealing mistake: Interior versus exterior views of the window sill/ledge are different when Brandon is aiming his rifle out. From inside the building, the window sill looks flat and the front tripod legs are close to the inside; from outside the window, the front tripod legs are over the window frame plus the ledge is layered. In some shots, it also looks like the window pane was opened horizontally to the left, but Brandon opened it by pushing it vertically upward to overlap the top pane. (01:00:43 - 01:01:41)
Continuity mistake: The way Brandon holds his rifle out the window changes. In some shots (almost every other one), Brandon is holding it at a downward angle (toward the people at ground level) but in other shots he is holding it straight out (parallel to the floor). Also, the man looking out the binoculars holds them straight out instead of at a downward angle. (01:00:43 - 01:01:24)
Continuity mistake: Before Lady Death attacks Brandon Beckett, the six garbage bags (near the front) are close to the wood block pallet (which appears to be a standard GMA @ 48"x40"), but after Brandon picks up one garbage bag to shield himself from her knife, there is more space between the garbage bags and the block pallet (which is now smaller, more like size 36"x36"). (00:34:39)
Continuity mistake: The kitchen walls were distorted (at awkward angles), but Zero got to the house around 6:46 and talked to Shelly for a short period of time. The now-blurred clock on the wall appeared to advance to almost 6:47, keeping a reasonably approximate pace with the scene's progress. However, only about 30 seconds passed until Brandon came in, but the clock (no longer blurred) had jumped to 6:50. (00:28:00 - 00:28:50)