It seems to break when zooming in/out on Firefox (Linux). Zooming in reduces the size of the viewport and makes clicking the mouse happen somewhere else.
I wandered about this a while ago, when VSCode went into Web. Later, after realizing how much download had to take place to have a remote OS ran, again the experience is very hacky with current hardware to software friction. It needs lots of drivers and resources to align experience with an actual OS.
As the author of this post, I have to say that I, too, was surprised by how well it's doing. But people at HN are generally very receptive to Lisp/Smalltalk posts, and lately, at least one Smalltalk-related post has appeared on the front page every week.
Use with caution.
Several of my friends love it.