Nintendo’s new Game & Watch re-release is based on new hardware, of course, not stuff from the ’80s, so people were able to do some interesting things with the code on the handheld. First, first Downfall
Stackmashing would have to make a few modifications to achieve this – like removing the world of textures – but hey, you do what you have to do to play Downfall
Note that only the beginning of the movie is “Man Playing Doom”. The rest is a detailed explanation of how exactly it was done. So if you want to find out how the 1993 shooter was squeezed and squeezed into a tiny handheld, check out the whole thing.