The "Awesome Ads with Alex" segment was not part of the script. Alex Voiovich came up with the idea to shoot an infomercial for his dad's book on the day of shooting and Noah decided to put it in the film as a parody of "Silly Songs with Larry" from VeggieTales.
During the dinner table conversation, some shots show Alex pouring hot sauce on his fish. This was improvised by Alex Voiovich, and the blooper reel shows the repercussions of him eating the hot sauce drenched food after the shoot.
The film itself is just under 8 minutes, but Noah Nelson included a blooper reel during and after the credits, which in addition to the post-credits scene brings the total runtime to 14 minutes and 41 seconds.
In the post-credits scene, Louis wears a Sonic Drive-In employee shirt. Noah Nelson has never actually worked at Sonic, he just bought the shirt from Goodwill as a joke.
The original plan for the ending was for the Cat and Alex to have a big fight scene in which Alex directly murdered the Cat, but this was scrapped when Alex Voiovich suggested a more psychological confrontation, which ultimately led to Noah Nelson writing in the poisoned fish as the cause of death.