In the scene in which the rats have "split open the kegs of salted sprats", the line "Send for Tybalt, the ratcatcher!" is heard. This is a reference to Mercutio's insult to Tybalt in Shakespeare's Romeo and Juliet, Act III, Scene 1.
The town of Hamelin comes alive in the style of Flemish painter Jan Brueghel with scores of actors, and, in one particularly eerie scene, hundreds of trained river rats filling its streets.
As an homage to the poem it's based on, nearly all of the story is told in rhyme.