Helga's Boyfriend / Crush on Teacher - S2-E14
Other mistake: Helga's Boyfriend: At the Stake Time roller rink, when Helga and Stinky are spinning around like a tornado, many of the kids are standing in mid-air. Brainy and Park are also standing in mid-air in an earlier shot where Helga tells Stinky, "Let's go!" (00:03:58)
Helga's Boyfriend / Crush on Teacher - S2-E14
Other mistake: Helga's Boyfriend: When Helga asks Stinky to be her boyfriend, as Stinky says, "Well, could you make it a Mr. Nutty candy bar?", you can see another Stinky sitting at the table at the far right. (00:02:16)
Helga's Boyfriend / Crush on Teacher - S2-E14
Other mistake: Helga's Boyfriend: At the start, Helga starts to profess her love for Arnold in the movie theatre. In this shot, Arnold's hair has four spikes on the right and three spikes on the left. Arnold's hair is supposed to have five spikes on the right and four spikes on the left. Also, just as Helga says, "your every action," Arnold's left side hair changes to four spikes mid-shot. (00:01:06)
Hall Monitor / Harold's Bar Mitzvah - S2-E15
Other mistake: Hall Monitor: After all the kids run into Phoebe, when Sid runs past her and her hat comes off, we can see that the hair above her scrunchie is yellow instead of black as it should be. (00:03:44)
Hall Monitor / Harold's Bar Mitzvah - S2-E15
Other mistake: Hall Monitor: When Helga is deciding on the new hall monitor and it shows a shot facing the crowd, many kids sitting in the back are faceless. (00:02:20)
Hall Monitor / Harold's Bar Mitzvah - S2-E15
Other mistake: Hall Monitor: When Helga chooses Phoebe to be the new hall monitor, as Phoebe is walking to the stage, Iggy's hair is incorrectly coloured black instead of brown. (00:02:30)
Runaway Float / Partners - S2-E20
Other mistake: Runaway Float: When Bob asks the kids who wants to ride on the float, Arnold says to them it's great the way it is. In one shot, Iggy's hair is incorrectly coloured black instead of brown. (00:05:52)
Other mistake: Ms. Perfect: When Mr. Simmons tells the class, "I have a note from Lila's father," his right sleeve briefly turns green. (00:19:22)
Other mistake: Ms. Perfect: When the girls sabotage Lila's lunch, as Helga pours out Lila's milk from her thermos, the milk crosses an invisible line and disappears. (00:16:56)
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)
Hall Monitor / Harold's Bar Mitzvah - S2-E15
Other mistake: In the credits, Justin Shenkarow is credited twice for voicing Harold. (00:22:59)
Tour de Pond / Teachers Strike - S2-E18
Other mistake: Tour de Pond: When Arnold, Gerald, and Grandpa are first shown at the Tour de Pond race, their ship is not sitting on the sidewalk, but rather on the edge of it, which makes it look like it’s floating in mid-air. (00:05:02)
Helga's Boyfriend / Crush on Teacher - S2-E14
Other mistake: Crush on Teacher: When Arnold and Gerald are walking to school and Arnold gets distracted by the birds and flowers, as he says, "Look at the flowers," his eyelids are not colored in. (00:14:37)
Helga's Boyfriend / Crush on Teacher - S2-E14
Other mistake: Crush on Teacher: When the kids are playing baseball and the baseball hits Arnold, as he says, "I'm fine, Miss Felter," his eyelids are not colored in. (00:13:02)
The High Life / Best Friends - S2-E10
Other mistake: Best Friends: When Arnold walks across the table during the fashion show, a small chunk of the spotlight vanishes mid-shot. (00:22:13)
The High Life / Best Friends - S2-E10
Other mistake: Best Friends: When Gerald is first revealed during the fashion show, the curtains are transparent. They are never transparent in any other shot. (00:22:26)
Runaway Float / Partners - S2-E20
Other mistake: Runaway Float: After Bob says, "Now this float has to scream 'beeper' at the top of its lungs!", as he walks away from Arnold and Helga, Joey is mistakenly drawn with white skin, blonde hair, and an orange shirt. (00:06:31)
Runaway Float / Partners - S2-E20
Other mistake: Runaway Float: When Arnold tears apart the big beeper on the parade float, the float's platform is missing, which makes it look like Bob and Nick are on the road. This happens again after Arnold stops the float, which makes it look like Bob and Nick are floating as a result. (00:10:19)
Runaway Float / Partners - S2-E20
Other mistake: Runaway Float: After Nick Vermicelli says that the parade float is a total mess, as Arnold says, "It's not a mess," the background is of the school hallway, not Arnold's garage. (00:05:28)
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.