In The Twilight Zone, the radio's sound clips that play during "Fast Lock" are taken from earlier Pat Lawlor pinball machines. In fact, starting the mode when one of the clips is playing cues the multiball theme from the respective machine to play.
Similarly, hitting the clock enough times during "Clock Chaos" will play a clip of Rudy (from Funhouse) yelling, "Stop playing with the clock!"
The semi truck has a plate with "CG" and a musical note; these are the initials of the game's musician, Chris Granner.
A bumper sticker reads "DL - JP", referring to designers Dan Langlois and Jim Patla.
A detached license plate near Betty and Marge reads "SK - 13", for design collaborator Steve Kirk.
One of the playfield road signs shows two merging arrows with the text reading "Williams/Bally Merge", referring to the (then) recent acquisition of Bally by Williams Electronics.
The globe on the backglass for Harlem Globetrotters On Tour includes a splotch of white paint next to Lake Michigan. Greg Freres painted the image during Chicago's notorious winter of 1979, and included that as a tribute.