I was wondering if going back to an earlier version of the game and speedrunning it in the current time is allowed since some exploits such as combo cancel (used by a controversal zerker runner here) do have a valid run still. I'm wondering out of curiosity. Technically anyone can downgrade their game to an older version.

Could you add the objective maps like Transit and Steamland for Normal difficulty?

This glitch he used is called combo cancel. I discovered it in 16th March 2018 but uploaded a video about it in the 17th March 2018. Here's the video:

Only reason the speedrunner who submitted it knew about it is because I told him about it. His name is Rango. My speedrun name is GKOOPZ but discord name is Brawler. Rango told one of the dev's moderator about it and reported the bug there in every way possible and got it patched, this means that you can't use the glitch anymore without modifying the game, so his record is forever doomed there because he purposefully got it patched. If his motives was to make it stay up there forever and make it unbeatable by making it impossible to duplicate it by reporting bug after abusing it in a speedrun, that could be possible but I can't fully confirm it. It's a shitty situation. I would recomend the moderator to take down his record as there are no way to beat it the same way he did it.

Emulators can give you an advantage, but that's why you have seperate categories between N64 and Emulator.