Continuity mistake: As the Cutlers set sail on the "Maid of The Mist" it's mid-day. Two shots later we see the boat in a long shot and it's late afternoon. (00:11:45)
Continuity mistake: The Cutlers take the Scenic Tunnel Tour and the attendant on the left is handing a gentleman a pair of boots. In the next shot he's standing around getting ready to laugh. (00:12:40)
Continuity mistake: At the bottom of the Scenic Tunnel Tour, Polly runs into Marilyn kissing her lover. At first the gentleman has his hands around her waist. Then in the next shot his right hand is holding her face. (00:13:45)
Continuity mistake: Both Marilyn and Jean's faces are dry as bones in the scene below Niagara Falls but Marilyn's lover is drenched. (00:13:50)
Continuity mistake: At night the Rainbow Cabins has a little outdoor party. The Cutlers are dancing together, and when the song stops Ray has his arms around Polly's shoulders. In the next shot his arms are around her waist. (00:16:35)
Continuity mistake: During the outdoor party at the Rainbow Cabins Marilyn walks out and asks the DJ to play "Kiss". No one goes near them but the three chairs that she passes on her right move about a foot closer to the record player when she walks away. (00:17:30)
Continuity mistake: Polly Cutler enters cabin B in order to put some Mercurochrome on George Loomis' cut hand. At first the yellow notice on the left door post is entirely in the light, then in the next shot as she walks through the door the lighting has changed and it's in the shade. (00:20:45)
Continuity mistake: George Loomis throws a lit cigarette at the ash tray on the table to the right of the door as Polly Cutler knocks. We see the cigarette smoldering on the table but two shots later after she enters we see the same spot again and it's gone without anyone going near it. (00:20:50)
Continuity mistake: Polly Cutler enters cabin B in order to put some Mercurochrome on George Loomis' cut and the do not disturb sign on the door knob is tilted to the left. No one goes near it but later in the scene it's been set straight. (00:22:55)
Continuity mistake: After Polly Cutler enters cabin B in order to put some Mercurochrome on George Loomis' cut hand the model car that he has been assembling sits on the table to the right of the front door. It moves closer to the ashtray as the scene progresses. (00:22:55)
Continuity mistake: As George Loomis goes over to the front door and shuts the lights so that Polly Cutler can see the falls in the dark, a pink sweater appears on the red and white chair behind him. (00:23:00)
Continuity mistake: After George Loomis shuts the lights Polly Cutler looks to the left at the falls in the dark, through the back window. This is the wrong direction as we see later in the movie as Marilyn has to look to the right to see the falls during the day. (00:23:15 - 00:36:15)
Continuity mistake: George Loomis goes over to the front door and shuts the light so that Polly Cutler can see the falls in the dark. The blinds on the left of the door are half open but when we see them again later in the scene, they're fully open even though no one has gone near them. (00:24:05)
Continuity mistake: In bed in their room Marilyn says, "Get me some orange juice Georgie" as she lays in bed on her side. In the next shot she's lying on her back. (00:29:30)
Continuity mistake: At the Scenic Tunnel Marilyn's lover writes a message to her on a postcard and places it back into the rack. She walks over and reads it but it isn't in the same place that he put it as the postcard next to it is different. (00:33:55)
Continuity mistake: Marilyn's lover writes a one line message to her on a postcard and places it back into the postcard rack. She walks over and reads it and we now see that there are 6 lines written on the back of the card. (00:34:05)
Continuity mistake: Ray Cutler runs out of the cabin office and says to Polly, "How do you like that?". In the overhead shot you can see tire marks on the gravel driveway but in the next shot there are none. (00:34:30)
Continuity mistake: At the Rainbow Cabins, Polly Cutler lays out on a beach chair sunning herself as Ray comes out to talk to her. There's a second chair about 10 feet to her right but the in the next shot it moves right up next to her. (00:34:40)
Continuity mistake: As Polly Cutler lays out on a beach chair sunning herself Ray steps back and decides to take a picture of her sitting there. Niagara Falls, which are always seen behind them are not in this shot, which has obviously been filmed on a sound stage. The bushes against the stone pillar are also different. (00:34:55)
Continuity mistake: Several dark marks appear then disappear and then reappear at different times on the Loomis's front door to cabin B. The marks are there during the party when George Loomis storms out and breaks the record, but then they're not there as Marilyn walks back into the room after speaking to the Cutler's. (00:36:05)
