Halloween - The Final Chapter - S8-E5
Continuity mistake: Roseanne becomes pregnant at the beginning of Season 7, and it is before the Halloween and Thanksgiving episodes, so she is in her first trimester during the holidays. However, Roseanne does not give birth until the following year in the Season 8 Halloween episode. Her pregnancy has lasted for well over a year.
Visible crew/equipment: When the Conners' friends come over and say "Hey Jailbird!" to Dan, a microphone can be seen coming down and going back up in the top left corner.
Visible crew/equipment: While Darlene is at the jail to post bail for Dan, when she says, "I guess I should prepare you for all the things that have changed," the boom mic casts a shadow on the wall, at the right side of the screen. (00:04:25)
Continuity mistake: When Roseanne is talking on the phone to Jackie, she continually moves around the kitchen while preparing dinner. The extra-long phone cord goes from being completely wrapped around her waist to just being behind her, then wrapped around her again, without moving in a way that would unwind it.
Continuity mistake: Darlene and Becky's second-story bedroom window is on the side of the house and at the house's backside (D.J.'s room is at the front). However, when the girls argue and throw each other's items out the window, everything falls into the front yard, as viewed from the living room. Even if they threw stuff from the house's front, the roof extends too far out below two smaller upper windows. Everything would land on the roof.
Other mistake: After the crazy guy threatened Roseanne when she was working alone at the Lunch Box, Dan wanted to teach her and Jackie how to use a gun for protection. Dan seems to have forgotten that Jackie was a cop for the Lanford Police Force and already is trained in firearms use. He regularly saw her in uniform with a sidearm.
The Pied Piper of Lanford - S3-E25
Continuity mistake: In Ziggy's first appearance in the series (S2, EP. 16 "Born to Be Wild"), he says he has two kids. He states "I had to make mine. I checked them at birth, they're boys!" However in his second appearance in the series here, he states they were his girlfriend, Jill's, kids and the kids are back living with their father.
Scenes from a Barbecue - S3-E24
Continuity mistake: Becky went from having long hair throughout this season to having very short hair in the last episode (ep. 23), then back to long hair in this episode (ep. 24).
Suggested correction: I'm not sure what the ruling on these types of mistakes is, but "Dances with Darlene" (ep23 and production code 425) was aired out of order. It was the last episode filmed in the season and meant to be a season finale, but aired prior to "Scenes from a Barbecue" (production code 423). One reason seems to be this is a Mother's Day episode and aired on the Tuesday before Mother's Day, and the next episode was Jay Sanders' last appearance.
Halloween IV - S5-E7
Plot hole: Just before Roseanne arrives at the Lodge Halloween party, Fischer is holding a small object in his hand that he slightly adjusts to a certain position. Roseanne then arrives dressed as Lady Liberty. When she raises her torch and asks someone for a light, Fischer immediately flicks on the cigarette lighter that he was already conveniently holding and ready to ignite for no apparent reason.
Plot hole: Before her date, Becky asks Roseanne to help style her hair. After the family teases her, Becky says she'll just do it herself. Shortly after, she comes downstairs with a perfectly executed and complicated French-braid hairstyle that would be all but impossible to have done by herself and in such a short amount of time.