Goofs

As Jack is lying face-up, his head at the tailgate of the truck, he beholds the naked sky for the first time. The world is passing by - from top to bottom of the screen. This is exactly the opposite of how he would see it from his established perspective. This is no small error for arguably the most beautiful moment in the film.

The morning after "old Nick" hits Ma, Jack sees the bruises on her neck. Later, she has the idea to pretend Jack's got the fever, but she remarks it has to be that day because the power was cut. Therefore it is established that it only has passed one day, but her bruises are gone. You can't see either purple, blue, green, yellow, as the common stages of it.

When Nancy and Jack get out of the car from grocery shopping, between cuts her purse changes back and forth from being held over her shoulder, to in her hand a few times.

When Jack is cracking eggs waiting for Nancy to wipe egg off his hands, the whisk in the bowl disappears out of the bowl without being touched, in fact is not visible on the table at all.

When Ma's tooth falls off and hands the tooth to Jack, the apple in his hand goes from his right hand to his left hand.

As Jack is eventually rescued on the outside, the police do not call an ambulance nor child protection. They take Jack into the car, go around in their car searching for the location, without proper care, going to the scene of the crime and potentially putting the child in harm's way again. This kind of policing would result in immediate suspension of the officers and a severe reprimand of the police department.

When Ma and Jack are trapped in the shed "room", there is a lot of time where old nick is not there. There is a window "skylight" on the top of the shed. There are multiple items that they could have broken the window with, and multiple pieces of furniture, in which they could have used to stack and climb out of the shed. This window was big enough for both of them to crawl out of. Instead s Ma chooses a different, much more riskier option of escape.

It may have been cut from the film but in the book, Ma explains that the skylight glass has a wire mesh running through it (Jack sees it and describes it as looking like honeycomb), rendering it unbreakable.

When they last visit the room, the door seems half open from inside. Ma even asks Jack if he wants it closed. When they exit, the door is obviously out of position, as the police must have broken it open.

Ma tells Jack to take his vitamin as it's the last one but there are clearly more rattling in the bottle both when she's holding it and when she puts it down.

The police cars say Akron Police Department and cars have Ohio license plates, but just about every scene that's outdoors in a non-residential area has recognizable Toronto landmarks (e.g. Nathan Phillips Square, Apache Burger, Victoria Mills silos, Prince Edward [Bloor] Viaduct). Also, Akron has 15 buildings that are over 150 feet tall, but the view from the hospital window has about 30 skyscrapers.

The accent of Tom McCamus, who plays the man who has lived next to the Newsoms all Joy's life, is among the details giving away that the film was made in Canada.

Whenever "Old Nick" was about to enter Room he could be heard from the outside sounding like he was coming up or down stairs but when Room was shown from the outside at the end, it wasn't connected to anything.

Short after Jack is picked up by Police and being questioned by the female officer, they guess what happened and alert the police office. Right after this, Ma got free and goes out of the secret shelter with the police help. This would be almost impossible to happen in a short period of time, with so short information given by Jack and also it would take several hours to find Ma exact location and also hard to understand she was inside the 'room' because is protected with no-sound walls and strong structure.

Given that Old Nick doesn't have much money and he is no high-tech nerd, he should most likely have used a simple digit keypad to lock the door without fancy logs or traps. Then Ma would literally have had all the time in the world during Nick's absence to try the 1,000 (4 digits) or 10,000 (5 digits) possible combinations to open the door.