When Sergei dies, he drops the microwave gun right beneath the alien that 'dusted' him. However, just a moment later, Ben picks it up as it is now lying at his own feet. It now has a blue, red, green, and yellow light on it. Towards the end, just before jumping into the river, the original microwave gun with the timer dial on the side returns.
The jetliner at the beginning of the movie undergoes several transitions while in the air and landing.
Inside the boat, when Natalie sits next to Sean trying to comfort him, his crossed arms over his knees keep changing position between shots.
The Moskva and Oka Rivers which traverse the city of Moscow are not deep enough to be navigable by ocean-going vessels. A nuclear submarine could not travel in it as far as Moscow without running aground.
Ocean-going ships use the Unified Deep Water System of European Russia and a sub could also. Of course, it would not travel submerged.
Ocean-going ships use the Unified Deep Water System of European Russia and a sub could also. Of course, it would not travel submerged.
When the electric-powered bus, the 'trolley bus' breaks free with Sean and Natalie on board, the bus makes obvious diesel engine sounds, although these do not have backup engines. The logic of the scene is that the bus moves without the overhead electricity line feed because the alien supplies power.
When the trolley bus starts, a combustion engine can be heard running although it is electric-powered.
When the characters have to jump off the boat into the river, Sean and Natalie both jump in together holding hands. All the characters except Natalie emerge together and climb aboard the submarine. Somehow Natalie has managed to end up in the city, clearly more than a few kilometers away.
She probably swam there, and it wasn't as far as a few kilometers.
She probably swam there, and it wasn't as far as a few kilometers.
The radio that the group finds in the US embassy works because it was protected from the EMP strike inside the bird cage, which acted like a Faraday cage. A Faraday cage blocks EM waves, including microwaves. The radio works in the bird cage because the antenna is connected to a wire leading outside of the cage, but it would not have worked in Sergei's apartment.
Unless Sergei knew that and foresightedly ran an antenna outside the cage.
Unless Sergei knew that and foresightedly ran an antenna outside the cage.
When the main characters are boarding the submarine, people are walking on the balcony of an apartment high-rise in the background.
Obviously some other survivors.
Obviously some other survivors.
Sergei has transformed his apartment into a giant Faraday cage he built as a protection against the aliens. It is not likely that he and Vika (if she contributed at all to this) could have set up the cage during the first four days of the invasion, considering the huge amount of material necessary.
He likely had had the material on hand since he was an inventor and it might have been in place before the invasion to protect his privacy.
He likely had had the material on hand since he was an inventor and it might have been in place before the invasion to protect his privacy.
In the mall, Sean discovers that the aliens can't see them through glass since they are reading human bio-electrical pulses and glass does not conduct electricity. So the bulb on Sean's neck should not be lighting up either.
The aliens are not causing the bulbs to light deliberately, it happens spontaneously when they are nearby. Seeing through glass has nothing to do with it.
The aliens are not causing the bulbs to light deliberately, it happens spontaneously when they are nearby. Seeing through glass has nothing to do with it.
As they float down the river on the boat to get to the submarine, traffic is visible in the background just as they go under a bridge.