Trivia: This is a very good example of the amount of detailed thought in these episodes. In S01E01 we saw Fry fall into the cryogenic tube and get frozen. In Season 5 Episode 8 (The why of Fry) we see this same freezing scene again but in this episode Fry and Nibbler are under the desk arguing since it appears Nibbler was the one to push Fry into the cryogenic tube. In Season 5 Episode 2 (Jurassic Bark) we see the freezing scene again but if you watch the scene where Fry is about to fall into the tube you can see the shadow of Fry and Nibbler on the floor since we learn that they are under the desk from S5E08.
Trivia: When the series first started, the animators placed five Alienese letters in the background. IN one poster, it said "drink slurm" and in another, drink was replaced by the five Alienese letters. Going on that, fans of the show were able to decipher the whole language in a couple of hours to decode what was written in graffiti on the wall behind the grate Bender and fry used to escape into the sewers. It said "Venutians (People from Venus) go home".
Trivia: David X. Cohen's name is actually David S. Cohen. He was asked why he changed the middle initial to an X and there are two explanations that he has given. Since there was another David S. Cohen who was member of the WGAE, it was necessary to alter the name, so he decided on the initial X change. One explanation for the letter X is because many aliens have an X in their name, and the other explanation is he thought it sounded cool.
Trivia: In the original ending for this episode (as seen in the DVD's deleted scenes), Bender says he'll be less like his old self when robot hell freezes over, to which Fry replies that it does freeze over during the winter. He reads this out of a book. In the aired ending, when Leela asks Bender to be less like his old self, he asks her if she could stand a 100' drop (or something), and Fry says "Good ol' Bender." However, you can still see the book in his hand from the original ending.
Trivia: If you watch closely, after Fry is leaning on the chair just after the countdown to ten reaches zero and he loses his balance, they cut to a close-up of the chair's legs falling over. You can see Nibbler's shadow cast on the wall in front of him. This was however retroactively added to the first season DVD. In the original airing of the pilot on TV Nibbler's shadow was not present.