Goofs

Midway through the movie the Man finds an unopened Coca-Cola can in a machine. When it falls out it has a dented top. When they drink from the can, there is no dent.

In the beginning of his narration, the Man says, "No animals have survived." But not only are people animals, but in the end, you see a dog with the other family. Of course, it's possible that this error is driven by his extremely limited perspective, or he might have meant no food/farm animals have survived.

The "current" portion of the movie takes place approximately 7-8 years after the "disaster" happened that caused all plant life to die off. If all plant life had died off, there would be no dry grass shooting from the soil, nor dead grass lying on the ground especially with all the weather turmoil happening around. All leaves and dried grass would have decomposed in that amount of time. Furthermore, trees would not have dried leaves hanging from the branches.

The Man is looking for gasoline in an old station but by that point, he'd have already learned that any fuel he might have found would be pretty much useless. Gasoline only has a "shelf life" of about six months. This can be extended by storing it in a vacuum-sealed container but even then, it certainly wouldn't last for years.

When the Man was at the gas station he tried pulling the trigger on one of the gas pump nozzles to see if it had any fuel left. However as the power grid is not functioning the pump would not work either, so using the nozzle would not be a accurate way to see if there was any fuel left. The only way to see if there was any fuel left would be to check the underground holding tanks.

If, as the film proposes, all plant life is dead, then human life would have soon followed it. SInce plants filter carbon dioxide from the atmosphere, then a lack of plants would allow for the increase of that CO2. And since the the unknown disaster appears to have been the result of a supervolcano, the additional CO2 would be accompanied by the gases from the volcano making the atmosphere even more toxic.

In the beginning, the Man is shown to only have two bullets in his revolver. But when we see the front the revolver after he cocked the hammer and pointed the gun at the urinating gangster we see two rounds in the cylinder. The cylinder will rotate again if the hammer is pulled back, so when he fired seconds later the hammer would have hit an empty chamber.

When The Man is forced to destroy the piano with an axe in order to create firewood to keep the family warm, a literal forest of dead or hibernating trees can be seen in the distance.

As all of the trees should have died some years before, at several points in the movie you can see conifers with full complements of what look like healthy needles, not bare branches.

It's wasteful to keep humans alive as food since captives still need to eat. Like any animal, butchering immediately and preserving through dehydration is more efficient.

Despite supposedly being deprived of food, neither of the main characters (nor most of the minor characters) seem to display any signs of malnutrition. They both have all of their visible teeth, their stomachs are not distended and they seem to have a large amount of energy to travel by foot over lengthy distances.

The sheer quantity of people that the man and boy encounter is absurd. If the majority of people worldwide are deceased, then the Americas, where the film is set, would be nearly depopulated. They should have not encountered many, if any, people simply because the survivors would either be in isolated town or cities or they would be holed in remote rural areas. SInce the two largely avoid the former and the size of the latter precludes easy visitation, they shouldn't have run into anyone for most, if not all , of the film.