Most films contain scenes or moments of dramatic intensity, where it's near impossible to turn your attention to anywhere but the screen. But to create an entire film where every frame is inherently captivating... well, that's not so common.
Films are all about pacing, after all; give audiences too much action, or ask them to stay at full alert for an extended period of time, and you risk losing them entirely. It takes a lot of energy to stay focused, so it's important for a film to ebb and flow. We desire those quieter and more cerebral moments just as often as we crave the more intense ones, after all - a difficult balancing act for any filmmaker to achieve.
And yet occasionally a director will throw caution to the wind in order to produce a film that attempts to keep the tension in the air for the sum of its entire runtime. A film that sets out to keep the adrenaline pumping from start to finish.
Usually this winds up going badly, and fatigue sets in after about 30 minutes (think Hardcore Henry, which felt like it had run its course with about an hour to go). But sometimes it does work, and what you're left with is the cinematic equivalent of a rollercoaster ride. The content is so original, so intense, and so absorbing, you dare not avert your eyes, not even for a second...