When Lisa is talking to Mr. Burns, her teeth turn blue on the left, and red on the right.
When Homer is eating toast in his mouth he is beardless but when it zooms out he does have a beard.
Homer arrives at work at 3:00pm (fashionably late?), but when he falls asleep and then wakes up he realizes it is 9:30PM, to which he phones Marge and claims "those 12-hour days are killing me!" Homer says at the beginning of the episode that someone punches in for him.
Burns drinks from 5:05 pm until 8:30 pm, but passes Homer at 9:30, meaning he stumbled drunkenly around the plant for a solid hour. Neither Homer nor Mr. Burns notice (or respectively choose to ignore) each others shortcomings, in this case Homer's sleeping on the job and Burns' drinking on the job, as Burns accuses Homer of working late, which Homer does not say anything else and accepts the compliment "You and I are a dying breed." The chance meeting has Burns believe Homer is a hard-working employee who can be trusted, hence the unraveling of the episode.
When Burns starts drinking, the glass disappears for a frame.
At the end of this episode, Burns' campaign for governor presumably ends in his defeat, yet the issue of the government threatening to shut down the power plant due to its numerous safety violations remains unresolved, and actually becomes a running gag in future episodes.
98% of Springfield voters see Mr. Burns as despicable or worse.
This is the first episode to be rated TV-14.
Mr. Burns's argument that the fish is a product of natural selection is validated by himself spitting the fish out. Tasty fish are more likely to be eaten by predators than bitter tasting fish. However by claiming during the campaign that the three-eyed fish would have "a taste that can't be beat" he caused his own political downfall.
What the nuclear safety inspectors discover at the plant:
Their Geiger counters show high traces of nuclear radiation before they even enter the plant's entrance gate.
Gum is used to seal a crack in the cooling vent.
A plutonium rod is used as a paperweight.
The pipes leak radioactive waste that is acidic enough to burn a hole through the clipboard.
The monitoring station is unmanned (due to Homer sleeping on the job).