A 2017 film (runtime 72 min) was repackaged in 2021 under a new title or as part of a Best of Korean Erotic Cinema series. Streaming services often change thumbnails and years to attract viewers.
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The "2021" in your query likely refers to a similar high-profile release from that year, (released March 17, 2021). This film follows a more continuous narrative: A 2017 film (runtime 72 min) was repackaged