Timberly Loves Arnold / Eugene, Eugene! - S5-E22
Continuity mistake: Timberly Loves Arnold: When Timberly and Arnold start crossing the street together, Iggy is standing far away from Rhonda and Sid. In the next shot, he is closer to them. (00:02:57)
Timberly Loves Arnold / Eugene, Eugene! - S5-E22
Continuity mistake: Timberly Loves Arnold: When Timberly asks Arnold if she can hold his hand while crossing the street, Iggy is looking at Arnold. In the next shot, he is suddenly looking away from him, then goes back to looking at him. (00:02:53)
Timberly Loves Arnold / Eugene, Eugene! - S5-E22
Revealing mistake: Timberly Loves Arnold: When Lila tells Arnold that it's sweet that he is hanging out with Gerald's sister, the stripe on her shirt is layered over her gold button for one frame. (00:05:33)
Timberly Loves Arnold / Eugene, Eugene! - S5-E22
Revealing mistake: Timberly Loves Arnold: When Lila says, "That is, if Arnold doesn't mind making it a threesome," her left eyelashes disappear for one frame. (00:05:50)
Timberly Loves Arnold / Eugene, Eugene! - S5-E22
Continuity mistake: Timberly Loves Arnold: Throughout the scene where Arnold, Lila and Timberly are at the lemonade stand, Lila is wearing her gold button on her shirt. When Timberly asks Lila if she wants to come to the baseball game, as Lila says, "I'm sure that I'd love to," she moves her hands, and for a brief moment, you can see that she is not wearing her gold button. (00:05:46)
Timberly Loves Arnold / Eugene, Eugene! - S5-E22
Continuity mistake: Timberly Loves Arnold: Throughout the beginning scene where Timberly is asking Gerald if she can come along with him, the blue accessories in Timberly's hair keep disappearing and reappearing. (00:01:07 - 00:01:42)
School Play - S3-E19
Continuity mistake: In the auditorium, when Mr. Leichliter says, "Indeed, it is I," there is no exit door on the wall to the left of him. In the next shot, an exit door appears on the wall. Later on, in a wide shot of the auditorium, the door is gone, and there are now double exit doors on the perpendicular wall. (00:05:22 - 00:05:57)
School Play - S3-E19
Continuity mistake: In the auditorium, when Mr. Leichliter claps and starts talking to Mr. Simmons, the location he is standing in changes three times. (00:05:19)
Stuck in a Tree / Rhonda Goes Broke - S5-E10
Revealing mistake: Rhonda Goes Broke: When Rhonda says, "I'm power walking. It's the healthiest way to get home," her mouth disappears four times. (00:21:42)
School Play - S3-E19
Continuity mistake: When Mr. Simmons tells the class about the Romeo and Juliet play, the projector has four legs. When the class is watching the presentation, it has three legs. Then when the kids leave the class, it has four legs again. (00:02:38)
School Play - S3-E19
Continuity mistake: When Mr. Simmons tells the class that they are welcome to come and try out for the play, there is no cap on the projector. When the kids start to leave, a cap appears on it. (00:03:18)
School Play - S3-E19
Continuity mistake: When Arnold is getting his lunch, his tray is empty. When he picks up the cup of green stuff and Helga gets mad at him, a milk carton appears on his tray. (00:00:29)
Helga's Boyfriend / Crush on Teacher - S2-E14
Continuity mistake: Crush on Teacher: When the kids are playing baseball and Miss Felter drives by, Harold starts walking to the side of the road, and Helga is standing on the road. In the next shot, Harold is already standing to the side of the road, and Helga is standing on the sidewalk. Helga's mask also disappears. (00:12:42)
Weird Cousin / Baby Oskar - S4-E11
Continuity mistake: Baby Oskar: When Oskar asks Suzie to make him breakfast, there are two baby food containers on the table. Later on, when Suzie is on the phone and Oskar walks back into the kitchen, the containers are gone. (00:16:14)
Weird Cousin / Baby Oskar - S4-E11
Continuity mistake: Baby Oskar: When Suzie says to Oskar, "Tomorrow, tomorrow, tomorrow. That's all I ever hear from you," she sets the baby bottle on the table. In the following shots, the bottle is nowhere to be found on the table. (00:15:23 - 00:15:57)
Weird Cousin / Baby Oskar - S4-E11
Continuity mistake: Baby Oskar: In the beginning of the episode, Suzie is ironing Oskar's pants, and the laundry basket is on the floor beside her. Suzie picks up his pants and lays them out on the ironing board, and in the next shot, the laundry basket is suddenly in her hands, and the pants are in the basket. (00:12:21)
Timberly Loves Arnold / Eugene, Eugene! - S5-E22
Continuity mistake: Timberly Loves Arnold: When Gerald says, "I could go for some Arnold lemonade," and Arnold pulls him in the alleyway, there is a building with a sign with the word "shoe" on it, written in red. In the next shot, it changes to yellow. (00:04:07)
Stuck in a Tree / Rhonda Goes Broke - S5-E10
Continuity mistake: Stuck in a Tree: When the firetruck shows up at the end, in Arnold's close-up, his sleeves are drastically shorter than usual. (00:10:29)
The Aptitude Test / Oskar Gets a Job - S3-E9
Continuity mistake: Oskar Gets a Job: When Oskar overhears Arnold and Suzie talking in the laundry room, he is standing next to the light coming from the room. As she starts to walk upstairs, he is suddenly walking out of the light area. (00:21:25)
The Aptitude Test / Oskar Gets a Job - S3-E9
Continuity mistake: Oskar Gets a Job: When Arnold and Suzie are doing laundry together, as Arnold talks about how Oskar was just fooling them all, he starts walking away from the dryer. In the next shot, he is walking away from the dryer again. (00:21:16)
Answer: The show is based in present day times. Plus most cars aren't old fashtioned, I recall seeing a limo and not to mention a cherry picker, etc.