Plot hole: In "The Conners" premier, Dan solely blames neighbor Marcy Bellinger for Roseanne's death after finding a bottle of opiates with Marcy's name on it. He only relents after Darlene shows him additional opiates that other people gave Roseanne and were hidden around the house. However, in the Season 10 reboot of "Roseanne", Dan had previously discovered and confronted Roseanne about her multiple opiate stashes, including one bottle with Marcy's name on it which he read aloud.
Continuity mistake: As Mark sits down next to Dan and reaches towards his backpack, in the very next shot he's pulling out a history book, even though he has not gotten anything out of the bag.