* AdaptationDisplacement: Nobody has heard of the book (''Literature/MakeRoomMakeRoom'' by Creator/HarryHarrison), but most people have heard about the movie, or at least "[[{{ItWasHisSled}} It's people! Soylent Green is people!]]" Which, incidentally, isn't in the book -- it's just a straight-up CrapsackWorld.
* {{Anvilicious}}: If we don't do something about the overpopulation we're all going sleeping shoulder to shoulder in the streets and stairwells, until we're turned into green biscuits!
** Keep in mind that the movie was made in the 70's. [[ValuesDissonance Birth control had only been legal for a few years and nobody took environmental protection seriously.]] You could argue that this movie was a [[SomeAnvilsNeedToBeDropped well-needed slap in the face.]] A self-''defeating'' prophecy, perhaps?
** ''Soylent Green'' is very similar to its contemporary ''TheDriftingClassroom'', which featured very similar themes. It came out in 1972's Japan, and proposed that humanity would drive itself into extinction through pollution and overpopulation before the year 2000, destroying the environment in the process. Both works have valid concerns, overpopulation and pollution are huge problems, but neither issue went in the direction they predicted.
* CrowningMomentOfHeartwarming: The dinner scene, when Thorn is treated to real food and uses a proper metal fork and knife.
* CultClassic
* FridgeLogic: [[Headscratchers/SoylentGreen Lots of it]].
* HarsherInHindsight: Roth's suicide. The actor playing him, Edward G. Robinson, was dying of cancer. Only Heston knew. And because of this, [[EnforcedMethodActing Heston's tears were]] ''[[EnforcedMethodActing real]]''.
* ItWasHisSled: Soylent Green is people. Like "[[Franchise/PlanetOfTheApes it]] was EarthAllAlong", It's now possibly the world's most poorly guarded secret, and has been parodied almost universally in Sci-Fi comedies and plenty of other places too.
* MemeticMutation: "It's people! Soylent Green is people!"
* NightmareFuel: "Soylent green is made from people!"
** The scoops. Imagine Trash Trucks converted with Bulldozers designed to scoop up the rioting populace. On the outside it seems like an important safety feature. However after the twist ending was revealed, it seemed that Thorn's prediction of the people being used as cattle came true.
** The setting itself. The OCEANS ARE DEAD! The literal source of life on Earth is gone! This isnt a dystopia story anymore, this is a mass extinction event! The humane thing at this point would be to just make a MercyKill for the whole species because there's no recovering from this.
* {{Squick}}: Depending on your squeamishness. The processed human flesh really doesnt resemble meat anymore, its just a wafer of protein. At that stage, its pretty academic.
* StrawmanHasAPoint: The nature of Soylent Green is certainly ghoulish, but it is ''literally'' the only resource left; the populace has a MortonsFork of either cannibalism or mass starvation.
* TearJerker: Sol Roth's suicide.