“Will it run DOOM!?” And as emulator maker extraordinaire Jean-Marc has now proven (and to be honest you may have already inferred from this post’s title), the answer is a resounding “OH YES”!
So, how did Jean-Marc squeeze all those demons and BFGs onto a Teensy 4.1? An STM32 port of Chocolate Doom certainly helped, as well as the fact that he had already developed a VGA driver. USB keyboard support, while it does not include complete mapping, allows you to enjoy the game as it should be: with arrow keys.
Source code and so much more can be found in the M.CU.M.E (Multi CompUter Machine Emulator) GitHub repo, along with information on the many other games and platforms supported by the project.