Continuity mistake: Towards the end in the staircase he tells her to run to apartment 4327, but they run right past it. It's on their right side in big obvious numbers. (01:25:17 - 01:25:51)
Continuity mistake: The sizes, locations, and smoothness of the pieces of glass remaining in the wall mirror after Aidan smashes it with a bat change. Initially, there were a few large and several smaller jagged-edged pieces around the top and upper-half of the right side. Later, there were four relatively large smooth-edged pieces spaced around the upper half of the mirror - one in each upper corner and one on each side at the middle. (00:15:48 - 00:19:33)
Continuity mistake: Brandon has sweat across the back of his T-shirt from his neck to above the arm pits (areas that were wet were darker blue) when Aidan tells him he had to leave his apartment. When Brandon turns around to leave, his shirt isn't as dark where it was wet, but now he has a V-shaped area of blood down the back of his shirt and his underarms and waist gradually get darker (wetter with sweat). (00:07:28)