1) you should add some explanation about why making light to through a number of crystals (they slow it down by 1/4 wavelength) lets the beam go though a beam splitter in one or two directions.
2) Pinch to zoom works but the photon beam moves on a path that's not affected by the zoom. Firefox Android, I didn't check with other browsers. But it works on a 4,7" screen, which is great.
My idea was to show who things work, rather than do any kind of textbook explanation. That said, I understand why this slow-down is mysterious (and deserves a better visualisation).
Thanks for info. Tiles are on CSV and the animation is on Canvas; I will try to see what's the problem (don't own anything with Android, though). In any case: I would be really, really grateful for creating an issue here: https://github.com/stared/quantum-game/issues.