When God makes it rain in Jerry's car, the shots of Jerry taken from Jerry's left side show his hair to be dry, but the shots taken from his right side show his hair to be soaking wet. These shots alternate several times, always with the same discrepancies.
The 1977 AMC Pacer wagon does not have the optional front vent windows through the film. In one scene where Jerry is pulled over by a policeman, the car now has small windows.
When Jerry tries to pick up Adam at school and Adam declines the ride, Jerry opens the car door and the open window is a few inches from being fully lowered (i.e., about 3-4 inches of window is visible). When Adam closes the door and talks to Jerry through the window, the window is all the way down; it is a manual window and could not have been lowered by Jerry in less than a second from the drivers' seat.
The location of the shaving cream on Jerry's face while he is shaving changes as the shots change.
Toward the end of the film when Jerry is driving away from the grocery store, he appears to be on a rural highway. When it cuts to a view of Jerry driving, the background is now an urban area with multiple storefronts.
When Jerry arrives to find religious fanatics in front of his house, the man with the signs is rotating them from back to front. In the next shot, he is rotating them from front to back. This isn't a goof, as the signs are all different sizes and have different messages, i.e., they aren't sequential. The man can pull these out in any order that he wishes.
[1:09:58]God comments that people speak so many languages that nobody can understand each other (see quotes). But according to the story of the Tower Of Babel (Genesis 11:1-9) It was God who caused people to speak different languages so they wouldn't have as much unity, but that doesn't make his statement here a goof. It is not.
[1:08:16]When Jerry is first shown in his hotel room, there is a telephone on the dresser. Reverend Willie Williams told him there would be no outside calls whatsoever, but they forgot to remove the phone from the room. This is a hotel, so incoming and outgoing calls can be controlled at the switchboard downstairs. There would be no need to remove the phone from the room.
After the newscast about Jerry, a hand wearing a solid blue shirt places the phone receiver on the base that is covered by a dish towel. The next shot reveals no one in the family is wearing a solid blue shirt. Since the phone was intentionally taken off the hook and the family is in the living, it is God that puts the handset back on the cradle so it will ring.
Near the end of the movie, as Jerry is walking out the back of the Food World store after being fired, you can see the Lucky Store letters on the top of the store facing the opposite direction (the letters are backward). Lucky is a supermarket chain in California.
Jerry's flesh-colored half-body suit is visible when he steps out of the shower to talk to God.
Back in the day when TV stations went off the air, the first thing that they did was broadcast a test pattern and make a high pitched sound. Eventually these went away in favor of no broadcast and no sound. When this happened, one's TV got what was called "snow," and a static sound. But when Jerry wakes up, his TV has the snow and the high-pitched sound. That "snow" should have been accompanied by the static sound, the high pitch that it had.
The trial for slander would have been a civil trial and would have taken many months, if not years, to come to trial after the alleged slander took place. Neither side would be permitted to call "surprise" witnesses at the trial. The witness list would have been made known to both sides well in advance of the trial as part of the discovery process, and each side would have had an opportunity to depose the other side's intended witnesses prior to the trial if desired.
When Jerry turns back to Mrs. Leven and Mrs. Green in the supermarket, a boom mic is visible near the mirror.
Near the beginning of the film, Jerry and Bobbie are getting ready for bed after having read God's initial note. Jerry blows his nose, crumples his tissue, throws it at the wastebasket, and misses. Bobbie mocks him, saying, "Air ball!" In fact, it is not an air ball, since it bounces off the rim.