Who Dunnit is a Midway pinball machine with a 1940s style and a murder mystery theme. The playfield features up to five different murder mysteries by revealing clues by sending the ball to an elevator, phone, or slot machine. The machine accepts up to four players and features four-ball play.

The game is set in 1934, and the player is Nick Spade, a hardboiled detective who is investigating a series of murders at a hotel and casino. Interrogate various suspects, gather equipment to help your investigation, and search for vital clues. Ride the train around town, search the sewers, then catch a taxi back to Tony's Palace. Use the elevator to explore the different floors of the hotel, then take a break by playing Roulette or the Slot Machine. Discover mysterious notes behind secret passages, watch out for ambushes in the Basement, then get up to the Roof and confront the killer. Play well and you'll get a chance for a Penthouse Party, but only the smartest gumshoes will figure out just how the fates of Tony, Victoria, Butler, Bruno, and Trixie are all intertwined.