Today we would call Demon Souls or Dark Souls a Soulslike
But when they came out the term Soulslike obviously didn't exist. So what genre were they referred too? Most likely 3rd person action RPG
That's what the video is trying to say. Doom came out before the term FPS was officially coined. The Catacomb 3D or Ultima Underworld examples in the video clearly show that first person didn't magically mean shooter. Finding keys, solving puzzles and fighting monsters in first person are things that weren't as genre-coded like we think today
The original Doom exe is programmed to have multiple actions that are common in dungeon crawlers. Opening doors, moving elevators, raising stairs, crumbling floors, damaging floors, crushers, teleports, keys, enemy ambushes. Most of these features would allow modders to recreate without issues, for example, a typical Zelda dungeon (
in fact someone already did!). The video even talks about Strife, a game built on the Doom engine which features RPG elements like dialogue choices and npcs. Today Doom is obviously considered the father of FPSs, or even simply a the father of Boomer Shooters (even if Wolf3D came out before). Doom being considered a "first person action adventure" (or first person dungeon crawler) in 1993 is a perfectly interesting discussion to have