Much like The Master, this is likely to be an unpopular choice, and the emotionally exhausting atmosphere of Stanley Kubrick's sci-fi masterpiece is for many just part and parcel of its appeal, even if 142 minutes is not an especially long runtime. It's the whole style that makes it feel long: the unbroken takes of "nothingness" are a bit of a challenge and a slog to get through without zoning out, in spite of the artistic excellence of these sequences on an aesthetic level. It's perhaps more of a pacing issue than the actual runtime itself, but at around 90 minutes, this would feel a lot more succinct, even if it might lose some of its epic appeal as a meditative sci-fi to switch on when you want to relax.