I've been running a game lately, I realised that the version one of the world records was done on has enemies respawn 5 seconds slower making the game much easier.

Every version of the game has the same respawn times now after an update 5 years ago and the old version gives atleast 30 seconds advantage. The category only has the console it's done on and not the version as well.

I'm going to try and contact a moderator about it but none of the mods really care about the game much. Which is frustrating cause I love this game and hold 2 world records in other categories. Would like to know what other people think.

Yeah you'll have to contact the mods and ask.

A sub category could be added to allow seperation between the versions.

Or the mods could allow, if possible, downloading the older version of the game to compete with the top runners.

If the mods don't respond and are inactive, you could submit a support ticket, saying they're inactive, to get the mods removed and you added as a mod instead.