Man Has Made His Match... Now It's His Problem
Why it is hard sci-fi
Set in 2019 Los Angeles after an off-world colonisation program has drained Earth of healthy people. The replicants are biological androids with a four-year lifespan engineered to keep them tractable. The film treats the Voight-Kampff test as a real diagnostic procedure for empathy response and gives it screen time. The world is grimy and runs on infrastructure that aged badly.
Science inside it
Telomere-style lifespan limits as a control measure, ocular biometrics, off-world colonial labour. The film predates modern transgenic engineering but the replicant manufacture model where each part is grown by a specialist firm is a clean read on a future bioindustrial supply chain.
Spoiler alert
The film leaves Deckards humanity ambiguous on purpose, and different cuts push the answer different ways. Roy Battys final monologue is the films thesis. He explains that everything he saw as a replicant is real to him, and then dies on schedule.