This is the third time a character is shown in pajamas. In this case it's Bird Brain.
This is the second time the show which takes place completely at night. The first time was in The Doomies.
Keswick reveals that he's from another universe called Keswickia, which is now destroyed.
This is the second time Dudley sang, the first time was in Kid Stuff.
The Chameleon's name is briefly seen during Bird Brain's flashback.
During Bird Brain's flashback, we see a picture of what appears to be Bird Brain without his monocle and a full head of hair. That may be a younger Bird Brain, or Bird Brain if he never prematurely aged.
Someone complaining about The Chief not paying the bills.
Kitty getting her gloves and jacket back on when Dudley pulled her and Keswick's T-shirts away from them, ignoring the fact that she didn't wore them initially.
When Kitty increases the amplifier output on Bird Brain's synthesizer, the highest note in the final octave is shown as a "B" which is erroneous since a 61 key synthesizer keyboard would have "C" as the highest note in the final octave.
Dudley & Kitty use their blasters at the first concert to save the monkeys, despite the blasters being given away.