I do love watching speedruns for games like Zelda, Mario, Splatoon 1 (and 2), among other games.
As for doing speedruns? I mainly speedrun Splatoon 2 like crazy; I'm even currently 11th place for the level "Tide Goes Out ~Bomb Rush Blush~".
Currently, I stand at a 4m 49s for the entire stage, using the Charger. Still aiming for the 1st place record on the leaderboards, as tough as it is, especially since I'd erased my entire save file's progress (Salmon Run records, multiplayer ranks, etc.)! But I still believe that I can soar past the record and be the king of that level!