In my opinion, setting Zoom level offset breaks the game a lot and makes speedrun very simple.

I suggest to create a separate category with this setting along with custom difficulty and mutators, and ban Zoom level offset on the main category. Or just ban this setting if you want.

(I'm writing because worried that my WR will be broken with this rubbish).

what exactly does it do?

It can greatly reduce scale of the screen in the game, and since scope of enemies gaze depends on the scale, you can literally finish the game without using weapons, using only fists. I personally checked it and you can do it too by changing this setting to +2.

I'll consider banning it