Other mistake: In the shot where the elevator door opens after the screenwriter hears the music playing, the control panel (for the basement) shows the building goes up to eleven floors. When the elevator opens on Floor 5, we can see the control panel on this floor only goes up to ten floors, despite being in the same building. (00:41:55)
Other mistake: When Mima awakens after supposedly getting hit by a truck, there is a calendar shown on the wall towards the edge of the bed. On the bottom row, there is no 28 shown on the calendar and the number 29 has been listed on the calendar twice, side by side. (00:52:36)
Other mistake: The calendar next to Mima's bed has the number seven displayed at the top, indicating that it is the seventh month of the year, which is July. But there are thirty days shown on the calendar page, when there are 31 days in July. (00:52:36)
Other mistake: After Mima sees the CHAM poster has been stuck back to the wall, there is a wide shot of her room. In the shot, there is a calendar on the wall to the left of frame, but the numbers are wrong. After the number 10, the calendar skips straight to 14, missing out 11, 12 and 13. Additionally, the number 21 has been repeated twice on the calendar. (01:09:33)