There's also a lot of not-so-obvious Easter Eggs, which you'd only catch in freeze frame - but the art book "The Amazing Maurice: The Art of the Film" (available from Paul Kidby's website, and amazingmauricefilm.com) has a lot more details about all of the design work that went into the film, as well as many of the more subtle easter eggs.
For example, did you spot that the fountain in the Bad Blintz town square is a statue of the Dragon of Unhappiness (arising from the toilet bowl) as mentioned in "The Truth"?
Highly recommend the art book for anyone who's a fan of the film and wants to know the sort of care that the filmmakers put into it.