Revealing mistakes: When Thorn is in the Soylent Green factory, he knocks two factory employees off the catwalk. A stunt mattress can clearly be seen sticking out from underneath the conveyor belt where the second one lands.
Continuity: When Thorn goes into the bedroom, the drink in his hand switches from a highball glass to a tumbler, then back to a highball glass.
Revealing mistakes: When Thorne is speaking to Sol in the suicide room, as the "Speaking Permitted" light blinks on and off, the audio cord on the panel changes position.
Continuity: When Sol is in the suicide theater his bed changes position.
Continuity: In the scene where Charleton "uses" the furniture, his ascot goes from on to off too quickly for him to have tied it.
Revealing mistakes: When Thorn is running towards the "going home" building, his head disappears into the matte just before the shot cuts. Later in the same scene, as he sees Sol "going home", part of his arm disappears behind the orange wall seen through the window.
Factual errors: Several scenes in the movie show characters using revolvers with silencers attached. Revolvers cannot be silenced.