Goofs

Samira's cat inconsistently appears in her bag.

The beers (background prop) in the pub scene change as the camera cuts from Stella Artois to a different beer.

When Samira walks through the group of people, a man in a fair isle sweater appears behind her in one shot (meaning she already passed him), but in front of her in the next shot.

When Samira is walking with the two kids towards the crowd, a Muslim man wearing a gray thawb is seen passing by front of her. A few shots later, the same man is seen coming up behind her.

When Samara sits down in the jazz bar, the stage area in the background is clear. After Eric leaves, there's a stool in front of the drum set.

With its sharp hearing the aliens can hear the minutest of sounds while being very far but they fail to hear the breathing of a person or heartbeat which can be heard by a human ear close to the nose or chest.

When Sam and Eric walk onto the platform of the Lexington Ave/59th St station, the lead car's headlight and line indicator are illuminated. If the power is out in the city, that would affect the subway lines. Subway trains get all the power from the "third" rail. If the power had not been out, they both would have been electrocuted when they descended onto the flooded tracks.

After jumping in the water, Eric pulls a letter from his pocket. It's completely dry despite him being completely drenched.

Calling a code blue in a hospice center would not be appropriate as the patients there are known to be dying.

The alien that chases Eric and Samira into the tunnels drowns after it's under water for a few seconds. The alien is an extremophile that was drifting through deep space on an asteroid, with no oxygen, so it would not have drown so quickly. One theory is that the creatures were sent by an alien race to wipe out humanity before invading, and hence would have been carried in some sort of spacecraft.

The military blow up the bridges to prevent the aliens from getting off the island despite the fact that the aliens are already on both sides. They were in fact blowing up the bridges, so boats could sail along the river, without the risk of creatures dropping from the bridges onto the boats.

The ferry carrying people away from the island is honking its horn as it moves along the river only attracting creatures along the shore. If the goal is protecting people, then the horns would have been disabled. However, it may be sounding its horn in order to draw creatures to the riverbank, and hence away from other parts of the city, where people are hiding.

One would think that it wouldn't matter if a generator makes a sound, as that would draw the aliens to the generator, not a particular person. However, since the aliens had only just arrived, it's unreasonable to expect any of the characters to understand all of the rules and nuances about what they can hear and in what situations. It's perfectly reasonable that people would panic about a noisy generator.

The military helicopters tell people to not make noise within the first twenty-four hours yet it is not until 400+ days that the Abbott family realizes to use high pitch frequencies to hurt the creatures. The Abbott family, by random luck, found a very specific high frequency which hurts the creatures, they are not affected by general loud noise ; perhaps like humans are particularly affected by the noise of fingernails on a chalkboard.

Throughout the film, various cars are shown to either be the EU-Spec versions of cars sold in the US & not sold in the US at all.

As shown in A Quiet Place Part II (2020) and this film, the aliens cannot swim and are afraid of water. However, in A Quiet Place (2018) one of the creatures willingly goes underwater in the Abbott's basement for an extended period making it an aberration.

The fentanyl patches Samira needs wouldn't be stored on the shelves where most pharmacy medications are kept. Pharmacies are required to keep controlled substances in a locked cabinet, and not just any cabinet, they have to use cabinets with two different locking mechanisms, they are mounted to the wall and are very difficult to break into. In addition most states require schedule II controlled substances like morphine and fentanyl to be kept in a time delayed safe, these safes are bolted to the floor, often weigh at least 750 pounds and are made from a highly heat resistant steel alloy. It would be impossible to break into one of these safes without making noise, and to do so one would need an industrial cutting torch.

The aliens are known to be blind but when they are chasing a certain person, they stop at the edge of the pier, somehow knowing there's water below that and they would be hurt by the water. How do they know there's water below the pier? They surely don't have sonars (if they had, all the story would've been different). And surely all those aliens haven't mapped all around the city.

Eric is a English character, played by an English actor. When he recites Samira's poem, he reads a phrase as "simple maths." Samira is an American poet; she would have written "simple math."