Love and Cheese / Weighing Harold - S4-E7
Other mistake: Love and Cheese: At the end, when Arnold says to Lila that he will walk her home, they both start walking to the right, then Lila vanishes while on screen. She never leaves the frame. (00:11:42)
Monkeyman! / Buses, Bikes and Subways - S5-E1
Continuity mistake: Buses, Bikes, and Subways: Helga wears a watch on her right arm throughout the episode. However, when Helga approaches Sheena's uncle Earl and wakes him up, her watch is missing, then reappears when Earl's boat sinks. It disappears again when Helga comes up from the water, then reappears a moment later. (00:18:59)
Helga's Masquerade / Mr. Green Runs - S5-E2
Audio problem: Helga's Masquerade: When Helga and Lila are at Slausen's Ice Cream, as Helga tells Lila, "About the way you're always going around acting so nice to people," her mouth stays closed until the word "acting." (00:03:21)
Helga's Masquerade / Mr. Green Runs - S5-E2
Continuity mistake: Helga's Masquerade: When Helga and Lila are at Slausen's Ice Cream, after Helga asks Lila how she can learn to act so nice to people, she grabs her milkshake with her left hand. A shot later, she is now holding it with her right hand, and a spoon appears in her left hand. (00:03:30)
Helga's Masquerade / Mr. Green Runs - S5-E2
Continuity mistake: Helga's Masquerade: When Helga and Lila are at Slausen's Ice Cream, after Helga asks Lila where she gets her material from, Lila's right arm is below the table, but a shot later, it's above the table, and a spoon appears in her hand. (00:03:18)
Arnold's Thanksgiving - S3-E14
Continuity mistake: When Helga is backstage preparing for the play, there is an "H" on the left side of her costume. When Phoebe tells her that she's on, she turns around and the "H" is not on her costume, then reappears a moment later. (00:03:32)
Girl Trouble / School Dance - S3-E18
Other mistake: Girl Trouble: When Arnold comes home after his rough day at school, his hair clips through the wall as he walks in the door. (00:04:39)
Arnold Visits Arnie / Chocolate Boy - S5-E12
Continuity mistake: Arnold Visits Arnie: In the country store, when Arnold says, "But, what about Arnie?" and it cuts to Arnie counting the bubble gum, the "1893" on the window is red but changes to white in the next shot. The "Est." also disappears. (00:05:53)
Arnold Visits Arnie / Chocolate Boy - S5-E12
Audio problem: Arnold Visits Arnie: In the country store, when Lulu tells Arnold to get some of the apple butter on the shelf, Arnold says, "Sure," but his mouth doesn't move. (00:05:41)
Arnold's Thanksgiving - S3-E14
Other mistake: When Arnold is in his room putting on his costume, his reflection in the mirror shows his buttons on the left side of his clothes. Then, when Arnold answers the door, his buttons are on the same side; the reflection was not reversed. (00:09:26)
Arnold's Thanksgiving - S3-E14
Continuity mistake: When Arnold's family is sitting around the table on Thanksgiving, there is a blue bowl with a spoon in it where Arnold is sitting. A few shots later, the bowl changes to white, and the spoon is gone. In the next shot, the bowl is blue again, and the spoon is back. In the shot after that, the spoon disappears again. (00:06:34 - 00:07:08)
Arnold's Thanksgiving - S3-E14
Continuity mistake: When the play finishes and all the kids are standing on stage, Arnold and Helga are holding hands. Arnold looks at Helga, and Helga pulls her hand away. When the shot changes, they are holding hands again. (00:05:17)
School Play - S3-E19
Continuity mistake: Lila's collar is gold throughout the episode. When the girls audition for the part of Juliet and Mr. Simmons says that they were all very good, her collar is white, and her gold button is missing. Then when Mr. Simmons says Lila will be the third understudy, her collar is gold again, but her button remains missing. Later on, when Mr. Simmons announces Lila will take the role of Juliet, her collar is white again, and her gold button is missing again. (00:08:46 - 00:14:26)
School Play - S3-E19
Continuity mistake: When Helga tries to convince Lila to drop out of the play, as she says, "What about that crazy costume you have to wear?", Lila's gold button is missing. It's also missing when Lila says, "I'm sorry, Helga, you're mumbling." (00:15:42 - 00:17:06)
School Play - S3-E19
Audio problem: Before the play begins, when Mr. Leichliter tells Mr. Simmons, "It's going to be a fiasco," his mouth doesn't move until the shot changes mid-sentence. (00:19:12)
6th Grade Girls/The Baseball - S1-E5
Other mistake: Sixth Grade Girls: When Arnold and Gerald are dancing with Connie and Maria, in one shot, Maria's left foot is incorrectly overlapping the right foot of the girl behind her. (00:07:32)
Arnold Visits Arnie / Chocolate Boy - S5-E12
Other mistake: Arnold Visits Arnie: When Arnold wakes up from his dream and he screams, his collar briefly loses its colour. (00:10:38)
Continuity mistake: Mugged: Throughout the scene with Arnold and Grandma on the bus, Arnold is not wearing his hat. When the creep runs off the bus and the camera shows Arnold and Grandma from outside the bus, Arnold is wearing his hat. (00:11:35)
Helga Blabs It All / Harold the Butcher - S3-E1
Other mistake: In the credits, actor Elliott Gould's name is misspelled as "Elliot Gould." (00:22:55)
Hall Monitor / Harold's Bar Mitzvah - S2-E15
Other mistake: In the credits, actor Elliott Gould's name is misspelled as "Elliot Gould." (00:22:59)
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.