Other mistake: In the scene where Tom Hanks and his son are riding in the car and Hanks is telling about the aunt in Perdition, a shadow is casted onto the hood of the car. However, the reflection of the clouds in the windshield never get blocked out.
Factual error: When Tom Hanks first drives into Chicago among all the 1931 era cars, a giant, modern, swing-arm, stationary crane is reflected in his car window. Also, The reflection of the Sears (Willis) Tower is seen in the car window as they drive along during this same moment, which wasn't started until 1970.
Revealing mistake: Half the time the Colt 1911s in this movie are fake. In the scene where Tom Hanks is killing all the mobsters in the rain and it's in slow motion, if you watch all the guys with 1911s firing, there are muzzle flashes, but no slide movement and all the hammers are decocked. You can also see this in the scene where Hanks kills Paul Newman's son. It's interesting though, because the muzzle flashes aren't added in later - if you watch the making of it on the DVD, you can see Tom Hanks firing one of the guns - they're basically shooting smoke and a reddish, somewhat fire-crackery looking red flame.
Continuity mistake: When Michael is teaching Michael Jr. to drive, the scene opens with the car parked tight on the right hand side of the road. When Michael Jr. pulls away, the car is in the middle of the road. (01:11:50)
Continuity mistake: After Tom Hanks kills Connor Rooney in the tub, Hanks shows up at the hotel room where his boy runs up to hug him. When they hug, Tom's arms around the boy are left over right, but in the next shot they're right over left. (01:43:45)
Revealing mistake: When Peter and his mother are being shot, note that Mike Jr., standing outside the house, hears the sound of the shots just before seeing the flashes. The slight delay between the flash and sound is probably pretty close, but he should have seen the flash before hearing the sound of the shots.
Continuity mistake: When Michael is sent to go get Rooney's suitcoat, he isn't allowed to get it, and when he appears downstairs just after coming from the study, Rooney is speaking, with his suitcoat on. Rooney didn't have time to get it.
Suggested correction: Mr. Rooney had a jacket on when he asks the boys if they brought the dice. Then, the next scene, they are in the basement shooting the dice and there is a jacket hanging next to him. So, the one in his study may be a different one.
Suggested correction: The scene where Mr. Rooney has his jacket on isn't immediately after the scene where Michael goes for the jacket because Connor, who stayed in the study, is also in the crowd listening to his Dad. And it isn't even the same jacket because when Mr Rooney asks Michael if he brought the dice he has his jacket on. And when they are shooting dice, it is hanging on something right next to him.
Plot hole: When Sullivan shoots Connor Rooney at the end, he flicks the door and we see the dead body. However the wall and some of the floor have loads of dried blood on it when he was only shot seconds before.
Revealing mistake: In diner when Hanks And Law are talking there's no food or coffee on the table. The scene switches to Hanks face and in less than a second goes back to Jude Laws face, and he's pouring sugar into his coffee that wasn't there a second ago.
Factual error: In the scene where Michael is going to get John Rooney's jacket, we are introduced to the character Conner Rooney. Notice that Conner is smoking a filtered cigarette. The movie takes place during 1931, but filtered cigarettes were not introduced into the market until 1936. (00:09:20)
Other mistake: At the time Tom Hanks hides behind the chest when being shot at by Jude Law, it doesn't seem possible that at that close range, he could hold the chest lid up against multiple shotgun shots.
Factual error: In the country church where Tom Hanks says a prayer, there is a bible sitting in the middle of the altar instead of the tabernacle. Prior to Vatican II, Catholic churches always placed the tabernacle in the center of the altar with the bible off to the side.
Continuity mistake: At the end of the film, when Tom Hanks' character is dying, we see his eyes slowly close as his son cradles his head. Yet in the next cut, when Hanks' character is dead, his eyes are wide open.
Continuity mistake: In the scene where Michael Jr. is riding home on his bicycle (before his mother and brother get shot) he drops his bike and runs to the house. A few minutes later when Tom Hanks is driving off with Michael Jr., it shows his bike. The bike has snow covered on it, but it is not snowing, the snow has stopped.
Suggested correction: It looks as though the bike is splattered with snow from the car's tyres.
Factual error: Some of the movie was filmed in the Conrad Hilton Hotel in downtown Chicago. Only in 1931 this hotel was named "the Stevens". Conrad Hilton purchased this hotel in the 1950's. Look closely and you can read the name "Conrad Hilton" written in script lettering. The lettering is out of focus on the wall in the background so you have to know what to look for.
Revealing mistake: Just after Mike Sullivan has taught Michael Jr. to drive, they are driving down a small track with a tractor taking up most of the road. If you look through the bushes on the right side of the track you can see a large modern road with metal barriers. (01:09:45)
Audio problem: When Tom Hanks ecapes from the hotel and Jude Law is shooting at him out of the window, you can clearly see a flash from Jude Law's gun but no sound.
Continuity mistake: After the night scene of heavy rains, you would expect at least some of the snow to melt the next morning. But if you look closely, the snow mounds in front of the Sullivan home are identical to the shots in the first few scenes, before the heavy rain.
Revealing mistake: When Mike and Mike Jr are driving down the road after Mike shoots Rooney's messenger the lights of a commercial plane flash twice in the night sky.
Continuity mistake: In the scene where Tom Hanks' son is reading with a flashlight under the covers, he turns the page and keeps reading, but he actually turned several pages. He is reading the Lone Ranger, so I don't think he would want to skip a few pages and keep on reading.