In this episode, we see that Dudley's brain is small and Kitty's brain is large.
After Dudley switched places with Kitty he was able to walk in her boots, later when he is at Our Old Hangout to meet Jack, he had a hard time walking in them, than when they got back to T.U.F.F., Dudley is able to walk in Kitty's boots again.
In Puppy Unplugged Kitty said that the Chief doesn't eat salad, but in this episode while covering for a lie, he wanted to discuss about making the perfect one.
When Dudley (In Kitty's Body) is eating the steaks and the cake off-screen, you can see small chicken bones, but Jack never ordered any chicken.
When Dudley begins to eat the jelly beans, it looks like he ate half of them. But in the next scene, the bowl is full again.
Kitty discovers that Dudley swapped her brain with his brain after she saw her in the mirror. But before he goes in, she (in Dudley's body) reads Dudley' note, as she hold the note you can see that she looks her hand so why she don't suspicious in that moment?
When Dudley (in Kitty's body) and Jack are in Our Old Hangout, he is wearing make-up and he has two eyelashes. But after he and Jack are in other places, his make-up is gone and he has one eyelash again.
In Bark to the Future, it has been said that when Dudley spells or write his name he only draws a dot and a circle, but in this episode, Dudley's name is in the note wrote by him (maybe this episode took place after Bark to the Future).
When Dudley and Kitty swap brains, Kitty's brain have problems to enter Dudley's head. But when her brain enters to Snaptrap's head, it doesn't seem that it have problems to enter even though Dudley and Snaptrap's heads are same sized.
When the shot of Kitty's brain entering to Dudley's head is shown, Dudley's front is taller than was before.
When Dudley says "But how can I swap brains with Kitty without her noticing?", the "Brain Switcher" nameplate doesn't have the word written on it.
Kitty falls back-first. But when Dudley swap brains with her, she appears to fell head-first.
Kitty's expression changes from sad to uncomfortable to sad again when she swap brains with Dudley.
Male characters keeping noodles in their shirts. Jack Rabbit is the only exception.
The running gag comes from The Wrong Stuff where phrases are actual places returns.