This is a little guide about how to disable the vertical movement of the mouse in the game doom 2, it's very simple so let's begin.
. . . Yep, it bother me too :/ . . . . . .
Download the fix
To disable this we are going to use a file named "Novert", to download it click on the next link (Erase all the asterisks ( * ) and enter it directly in a browser, srry guys new steam Steam policy doesnt let me put a direct link): "https://mega.n***********z/#!ClxzSArT!uC*********Lz2wsfdzLGyIKw2V0XNpE_rE_vegigrUpWUveUF6Y" you will open the next window: once you download it, you get an winrar file, extract it nice, now you have the program now let's add it to your doom, go to the next section.
Add the fix
Search your Doom 2 folder, it's usually installed on C:/Programfiles/Steam/Steamapps/Common/Doom 2 Once you find your Doom 2 folder open the folder "base", now move the file "novert" to this folder (base).
now in the folder "base" find a file called "doom2m.conf" (beware with the other one called doom2.conf, we are looking for doom2m.conf) you can open it with a text editor like notepad, once you open it go to the end of the text and search for this line:
now you must type "novert" in that line (below "c:", and up of "doom2.exe -config MOUSE.CFG") it should looks like this (click on the image to amply) :
And it's done, you removed the vertical movement of your mouse while you tried to aim, ¡enjoy! :)