I like how this puts SVG elements directly in the page's DOM; seems like a great way of making interactive vector graphics in a browser. Unfortunately, in Firefox I occasionally get rendering errors when the tile I'm pointing at is highlighted. Sometimes weird things happen after clicking a tile and then pointing at a neighbour[0], but mostly it looks as if re-rendering ‘dirty’ areas and updating the framebuffer are somehow getting out of sync[1].

It's not super annoying, though, because moving the pointer over the affected tiles accusatorily[2] cleans them up.

On an even more hair-splitting note: The tile grid looks slightly wonky instead of perfectly regular. (The borders/gaps between hexes have different thicknesses.) I think this is because the coordinates of vertices are rounded to integer pixel coordinates before rasterisation? I'd suggest trying this: Instead of going for exactly regular hexagons, deform them very slightly so their vertices have integer pixel coordinates. Due to the zoom feature this isn't the most trivial fix ever, but on lower-resolution displays it would look a lot neater[3].

Oh, and a feature request: There should be alternatives to ‘mouse wheel’ and ’middle click & drag’[4] for zooming and panning. Input devices on which performing/emulating these actions is inconvenient (or even impossible) aren't all that uncommon. (E.g. how do you middle drag on a trackpad?) Panning could be done with a regular (left) drag. For zooming, there could be −/+ buttons in a corner, or hotkeys, or right dragging, or dragging while holding a modifier key. Not using scrolling for the zoom function would be nice for players with input devices that have omnidirectional scrolling: They could use that for panning instead. I think it would be fine to keep the defaults as-is, but an option to switch it up in the ‘ESC’ menu would be nice for accessibility.

[0] https://i.paste.pics/AE7L2.png [1] https://i.paste.pics/AE6X1.png [2] Fun fact: Firefox's spelling checker doesn't believe that this word exists and suggests ‘satisfactorily’ instead. [3] https://i.paste.pics/AE7JD.png [4] Which should actually be called ‘middle [button] drag‘, but I'll spare you the off-topic rant ;)