Reflex runs, boss-fight nerve and the way people actually behave with a controller in their hands.
In a laboratory, simple reaction time is measured with a fixed stimulus, one prepared response, dozens of trials and hardware that timestamps the button rather than the browser. Figures for a visual cue tend to land somewhere near a fifth of a second, and the genuinely interesting finding is the spread: your own results vary more from trial to trial than most people's averages vary from one another. Sleep, caffeine, whether you were expecting it and how long you had been waiting all move the number around.
A quiz page can do none of that. Between the display refresh, the operating system, the browser event loop and whatever your keyboard's polling rate happens to be, tens of milliseconds disappear before anything has been measured at all. So the questions here ask about behaviour instead, where you sit in the lane, when you commit, what finally makes you put the pad down, which is at least honest about what a page like this one can see.
Arcade design grew up under an economic constraint that home consoles never had. A cabinet earned by the play, and an operator wanted somewhere in the region of a couple of minutes per credit, so difficulty was tuned to end a run at a moment that felt like your own mistake rather than the machine's greed. The forgiving opening stage, the sharp step up in the second, the boss with a pattern you very nearly read in time: those were commercial decisions dressed as design ones, and they worked because the disappointment always pointed inwards.
It left behind a craft worth admiring. Attract modes that taught the rules to a passer-by with no tutorial and no text. One button doing three different jobs depending on context. Three initials as the entire social layer, and a queue of coins on the bezel as the booking system.
The part that has aged best is the principle that a player must be able to see why they lost. Difficulty is cheap; legibility is expensive. Being killed by something off-screen costs you the same run as being killed by an attack that was telegraphed, but only the second one makes you want another go, and everything people mean by hard-but-fair comes down to that difference. Treat these quizzes in the same spirit: a bit of fun about controller habits and nerve, with nobody's reflexes actually on the stopwatch.