Oswald Cobblepot introduces himself to James Gordon and Barbara Kean as "Peter Humboldt". "Humboldt" is also the name of a species of penguin.
The spring-loaded monocular that fatally penetrates the eye of an unsuspecting viewer when focused, was similar to the lethal binoculars used in Horrors of the Black Museum (1959) that featured Michael Gough. Gough went on to play the British butler Alfred Pennyworth in Tim Burton's Batman movie series and his character is portrayed here by British actor Sean Pertwee.