There have been lots of complete games built targeting the web browser. Crosscode is pure HTML5 according to the devs. No webgl at all. Games like Quake have

There have been lots of complete games built targeting the web browser. Crosscode is pure HTML5 according to the devs. No webgl at all. Games like Quake have been ported to run in the browsers (and did so ~10 years ago). I'm sure there are a lot more complete games out there targeting web browsers, but it isn't immediately apparent that's what they are using. A lot of the newer games I play feel like they are running in a web browser.