Two observations:

1. At the very beginning of the movie, there's a scene where The Penguin, as a young child, is put in a cage because of his freakish appearance. On a wire hanging just outside of the cage is a rubber ducky, which forshadows the giant rubber duck that Penguin uses to attack Gotham City later in the film. The young Penguin also manages to yank an an animal through the bars of his cage and eat it. That animal? A cat.

2. Later in the movie, the Penguin threatens to kill Max Schreck by submerging him into the same toxic filth from his company that has polluted the sewers of Gotham. Penguin makes direct note of this irony. How does Max really die though? By being electrocuted with the tazer that Selina Kyle, ne Catwoman, had stolen off of the circus gang member. If you'll recall, though, the reason that Max killed Selina in the first place was... because she discovered his nefarious plan to suck electricity from the city and resell it. A death just as poetic, then, but totally understated.