Well lets get started the shall we, this guide won't really require any special tools,
that doesn't already come with your standard OS like notepad.exe

However In this guide I will be using Notepad++, but notepad will also be adequate.

I am going to assume that you already have installed the game through steam.

First off we need to edit the files that we will need that the shortcut,
will use to run the game.

To find these files you need to go into the game properties of Heretic,
by first right clicking on the game, then choose properties.



Then you should see the window of the properties of Heretic,
to locate the files, press on tab Local files, & then click on Browse Local files button.



Then your file explorer should open, displaying the folder with the following files,
in the folder base is where dosbox is installed for heretic & where you will find the game files along with the executables.




First edit the file Heretic.bat, in that file there should only be 2 lines, in it,
in the first line delete the text "-fullscreen" as shown in the picture.




Next open the folder base, and edit the file heretic.conf, in the line fullscreen edit it from true to,
false, and the window resolution you set the resolution of the window, you can use the following example in the picture & set it to "1280x960"



Or you can use another resolution type, show in the link here:
https://en.wikipedia.org/wiki/Display_resolution#/media/File:Vector_Video_Standards8.svg

Remember to use one of the resolutions that are marked in red since the game is made to display in a 4:3 format.

For now all we have is a bat file which launches the game in Window mode,
now we need to create the steam shortcut which launches the bat file, I will also give you a way to apply the Heretic game icon onto the shortcut.

First you add a none steam game, in the bottom of your game library, you will find the option,
to add a game, & then add a non-steam game, first you just pick any random exe,file doesn't matter which, that will be changed further in the guide.

Just for clarity in this example i choose the browser called brave.exe file.


Next you need to find the new game you added onto stean, then right click on it, & choose properties,
so that you see a similar window like this:



Next then press change, then you need to locate you steam folder, you will usually find it in "C:\Program Files (x86)\Steam"

Then you proceed into the folder "Steamapps" -> "common" -> "Heretic Shadow of the Serpent Riders" & then you choose the bat file heretic.bat

If you can't see the file then change the file type to "All files (*.*)"

Then you can edit the name of the shotcut to something fitting like "Heretic: Shadow of the Serpent Riders (Windowed)".


Lastly all you need now is the Icon for the heretic shotcut, problem is it's actually not included in the game files, so I have supplied a link to the following Icon so that you can download it.

I would recommend saving the icon in the "base" folder, of "Heretic Shadow of the Serpent Riders"

Icon Link


After downloading the icon you will require to convert it into a png file in order to use it as an Icon,
which can easily be done in simple image editors like paint, where you save it as a .png file.

Then you choose icon in the shortcut properties, then find the folder for "Heretic Shadow of the Serpent Riders" like you did before, & choose the icon in the "base" folder.

Now you have a shortcut of Heretic, which launches the game in Window mode.