Hm. This is very strange. It seems that this is exactly some kind of rendering problem related to the browser and platform (I sometimes have artifacts in Chrome for Windows related to the scrollable parallax background sometimes), and it is possible that this is due to on-screen postprocessing, however I can't figure out what the problem is yet. It will be necessary to study this issue in more detail.
In order to port the game from Windows to the WebGL version, I had to disable or replace some shaders, because they did not work in the browser. As I wrote above, WebGL has two versions of the graphics API, the first version is usually used, but I used the second one because I use linear colour space and HDR. But the second version of WebGL should be supported by everyone, because it is already 7 years old (but this does not mean that it works equally well), but in any case WebGL's capabilities are very limited. Also, the WebGL engine is different for Windows and for Mac, for example, in Chrome for Windows, it forcibly uses DirectX, which I was guided by (to be honest, I have never worked with OpenGL and Metal at all, I have always worked exclusively with DirectX and do not know what is beyond it), while in Chrome for Mac and Linux, OpenGL is used (at least it used to be early before Metal, I don't rule out that Apple might have changed something). Moreover, different browsers have slightly different WebGL engines, but I did not expect that there might be problems on MacBooks 0_0 I will need to see if possible how the game works from under the browser in Linux, it may be interesting :-)
However, I was able to run the game even in browser on my phone lol, it looks exactly the same as on Chrome in PC, only the game input has gone mad and something is wrong with viewport, but it was expected :-)
However, this is not Chrome, this is a different browser - Yandex-browser :-) Chrome on my phone, couldn't launch the game - it just freezes at start :-) In other words, the behavior differs from browser to browser even on the same platform...very interesting. I expected that WebGL's behavior would still be more predictable, it would be good to understand what exactly causes such things...