Amazing prototype by Ryan C. Gordon (@icculus) with the introduction of UT99 running natively in a browser via emscripten.
As more and more moves into the browser it was just a matter of time before something like this happened, there has already been a faux-browser based quake client for a while via the quakelive which worked quite well and up until the sale of id Software to Zenimas was crossplatform. We have also seen the internet archive compile Mame for the browser and integrate it directly into the archive.
To be absolutely honest, We never thought we would see UT99 in the browser. Now not only does the client run natively in the browser but work has been done to add network connectivity via some web socket voodoo which will connect to existing servers across proxied web sockets.
Perhaps it is just us but this is amazing. While it is currently not playable we can see a future where we could self host the client files for connection to our servers via the browser… this is the stuff of dreams