Make an actual realtime option where you need to struggle to meet the clock. 1h + 5m can be REAL slow at times and still both players end game with 1h left. 30m + 3m or something like that?

Looking at the markup it seems every "object" is redefined upon use. Like every mine has its own geometry defined over and over. I think performance could be improved if they relied more on:

https://developer.mozilla.org/en-US/docs/Web/SVG/Element/use

so that shapes can be reused. Its just a guess so, but I think its a good one.

I prefer to play with opponents of a similar level as myself. If I end up against a 300 elo player when I'm 130, chances are I'm gonna be outplayed. I guess many agree with me that tight games are the best - when its down to the 0-5 points in the end. Would be great if you could just set a min/max range for joining a game. Or a predefined range(s) around your own.