In the drugstore, the opiates would not be just sitting out on a shelf. They would be inside a locked safe that can be opened only with a security code. Not storing opiates securely is a criminal offense.
When Reese examines the old two-way radio, she clearly discovers it is powered by a standard 120-volt AC plug. Somehow, simply connecting a 12-volt battery powers it up.
In the drugstore, Frank picks up a big bottle of penicillin. There is almost NO plain old penicillin in drugstores now, because so many pathogenic bacteria have become resistant to it. It's been superseded by hundreds of newer antibiotics. That bottle of penicillin will cure almost no common bacterial infection if Frank tries to use it.
Right after the E.M.P. hits, Reese is on her laptop stating that's there is no internet, but is looking at pictures. After an E.M.P., nothing electronic will work. That includes computers, cars, radios, watches, pacemakers,etc.
Her grandfather said she had to be within 5 miles of his location to use the short wave radio. As soon as she starts the journey with her dad to reach her grandfather, she uses the radio to contact him. She was about 20 miles away at the time and the short wave radio would not have worked.
When Reese opens the book "Radioflash," it doesn't seem to have a title page. She opens it right to a page that incorrectly uses the plural form "phenomena" instead of the correct singular form "phenomenon."
The actress playing Reese incorrectly says "nucular" instead of "nuclear." She should have been corrected by someone on set.
When the grandfather goes in search of them he comes upon tire tracks showing vehicle went off the road down a hill. He should have been coming from the opposite direction, as they were trying to get to him. He should not have been heading in the same direction as they were when they left the road.