Capture the output of DOOM (typically the dos port where the screen is super simple to read as a byte array). Do some filters on it. Render it somewhere else. YAWN.
For me, it is more about just the low-effort "ports" like this (e.g. where they just render it there).
However, I enjoy seeing more creative and actually novel ways of "DOOM running on xyz". One such example would be DOOM actually implemented in Excel. Back when it came out, it was genuinely cool and novel. This is the type of stuff that I would not mind seeing more of at all.