Continuity mistake: Before the telephone melts the label of the bottle keeps moving around.
Continuity mistake: Halfway through the film, Mike is wandering inside the room and knocks down a red vase. A second later it appears back on the table.
Continuity mistake: Mike fixes the boat painting, his hair and face are dry. He turns around and sits down and now he is all sweaty and with messy hair.
Continuity mistake: Mike goes to the window, leaving a can, food and a bottle on the night table. When he comes back only the bottle remains.
Continuity mistake: When Mike falls down from the ceiling, he falls on his back, but a second later from a closer angle he is crashing on the table on his butt.
Continuity mistake: In the scene Where Mike Eslin's hotel room has frozen over and he is laying on the floor talking into his recorder he notices his computer turns on and his wife is talking to him. As Mike tries to get up you see his head touch the alcohol bottle, in the next shot that is further away from Mike you see the bottle is much further away from his head then it should be.
Continuity mistake: When Mike reaches the phone and hears the operator asking if he is checking out, the phone on the table swaps from facing down to up between shots.
Continuity mistake: While Mike is presenting his book, the cigarette on his ear is semi-hidden by his hair. Half a second later the hair appears shorter and the cigarette is visible.
Continuity mistake: When Mike goes to the window to call for help, his doppelganger across the street is mimicking Mike's every move. After waving their arms in mirror-image synchronicity, Mike leans to his right slowly, and so does the doppelganger, but it should have leaned to its own left to mirror Mike's movement. All its other movements are exact mirror images. (00:45:10)
Continuity mistake: When Mike steps off the elevator, he is between the elevator doors and a dark statue in the middle of the hallway. The statue is seen behind him, slightly to our right. When the elevator doors close, Mike's location is different as he begins to walk down the hall. Relevant to the earlier shot, he is much further to our right and farther from the elevator doors, as now has to walk around and past the statue he was originally already past. (00:25:15)
Continuity mistake: Mike enters the hotel and a woman in the back, sitting next to the woman with the pram, disappears between shots.
Visible crew/equipment: When he is fixing the crooked ship picture in the somewhat dark room in the reflection behind him you see an arm with a light blue short sleeve shirt in the glass door.
Continuity mistake: When Mike is in the room holding his crying daughter, the blood trails from his nose and ears change constantly between shots.
Continuity mistake: When water starts to pour in the room Mike's hair is totally messy, except for a brief shot where it looks perfectly combed, and then back to messy.
Continuity mistake: The cognac bottle magically refills itself after frozen Mike chats with his wife.
Continuity mistake: As Mike catches the attention of his mimic in the apartment window across the street, he makes two distinct gestures with his hands to signal distress: the first being the "hand phone" imitation and the next pointing downwards. Right before the mimic begins reflecting Mike's movements, Mike is shown making this sequence of hand motions. However, as the camera pans to the mimic we can see its movements are off-sync with Mike's, incorrectly continuing to point downward when it should be mimicking Mike's phone gesture. (00:44:50)
Continuity mistake: When Mike falls on the frozen floor, after chatting with his wife, the vase swaps from being covered in ice to semi covered between shots.
Plot hole: Time inside room 1408 moves differently than time outside it, as evidenced by the fact that Mike spends weeks or even months in what he thinks is his home in California, while in reality he is still "in" the room. The Hotel's manager states that no one has ever lasted more than an hour inside 1408. He goes on to cite many examples where the guests died after just a few minutes. No previously sane individual commits suicide after spending a few minutes in an eerie room, obviously, so the only explanation is the one offered by the "receptionist" over the phone, albeit in fewer words: guests in room 1408, while experiencing their own time frame inside the room, are in fact reliving the same hour over and over according to the rest of the world's time frame. This being the case, Mike's ex-wife should not have showed up at the climax since Mike's hour had just started over, undoing the call he placed to her earlier in the film but later in the hour. Whether or not the film makers intended this inference is irrelevant as the movie plainly lays out these conditions and must therefore adhere to them lest a plot hole be created. [This keeps being debated back and forth - ultimately there's not going to be any absolute resolution, so it's being locked down as a mistake and viewers will just have to make up their own minds - Jon.]
Continuity mistake: While Mike is signing books, a fat guy bends over next to him. Angle keeps swapping in a matter of seconds from front to back angles and he's always there, except for a moment from the back when the guy disappears, only to appear again in the front angle.
Continuity mistake: The amount of snow on Mike's forehead when crouching on the floor, increases and diminishes between shots in a matter of seconds.
Chosen answer: He sums up the individual numbers: 1+4+0+8 = 13.
Twotall