[imiric]

I don't think that's a fair performance bar to set for web apps, or even native apps. The 16ms window for games is used to process input, shuffle data in very fast memory, do calculations, and render a frame on a very fast GPU specifically built for that purpose.

Web apps can also render frames in 16ms, but input often involves fetching data from much slower and unreliable disk or network, processing data on a much slower general purpose CPU, and rendering it via runtimes and frameworks that add considerable overhead. Given all of that, 50ms (20 FPS) does sound very responsive, if maybe not breathtakingly so.