Running DOOM (Sort Of) on a Sonoff Smart Switch

It’s often said in this community that DOOM can be made to run on anything, and as time goes on, that’s becoming more and more accurate. We’re at the point now that every “normal” device seems to have some version of the iconic 1993 shooter, so now there’s nothing left but to start working on the more oddball targets. As a perfect example, [piuppi] recently wrote in to share their efforts to get DOOM — or at least something that looks like it — running on the Sonoff Basic R2 smart switch.