Hi, I hope this guide will get the Steam overlay for DOOM II working for you.

It's fairly straight forward, and I try to "For Dummies" this guide as much as I can. Feel free to ask anymore questions you have, and let me know if I should add a step or something to a step.

The overlay will allow for screenshots, broadcasting and everything else the overlay gives. Launching with custom settings with the Steam launch options also becomes available.

Things you need:
Windows OS. (This guide is done with 7 but I imagine it'd work with 8/10 and probably XP.)
DOOM II on Steam. (Duh.)
ZDoom, or another source port. If you choose another, you should have some knowledge of it to troubleshoot any differences. (Although there shouldn't be many.)
Notepad++, a file editing program.

Links to mentioned downloads: (Will be provided again in the guide when you need them.)
ZDoom: http://zdoom.org/Download
Note: As of 1/7/2017, ZDoom is no longer updated. Like I state in this guide, this should work with most sourceports. So you may want to consider another, like GZDoom[gzdoom.drdteam.org]. Source: http://forum.zdoom.org/viewtopic.php?f=1&t=54883
Notepad++: https://notepad-plus-plus.org/download/

Note: As of 1/7/2017, ZDoom is no longer supported. Like I state in this guide, this should work with most sourceports. So you may want to consider another, like GZDoom[gzdoom.drdteam.org]. Source: http://forum.zdoom.org/viewtopic.php?f=1&t=54883

This will most likely work with most source ports, but for this guide I will be using ZDoom for my examples. I assume as long as you can get to step 5 with your source port and have it launch through Steam, the rest of the guide will work.


Just click the Windows logo on http://zdoom.org/Download

Unzip zdoom with whatever program you use (I use winrar), you should get a now unzipped folder.

In that unzipped folder, rename "zdoom.exe" to "dosbox.exe"

Copy the 4 files you recieved from ZDoom, and replace the dosbox.exe in there with your newly renamed one.

You should now be able to launch DOOM II from Steam and it will launch ZDoom.

You're are about to edit a file called appinfo.vdf, and to do so you will need Notepad++

Download: https://notepad-plus-plus.org/download/
Install NP++

appinfo.vdf is usually in "C:\Program Files (x86)\Steam\appcache", but it will be where ever you installed Steam at.

Right click appinfo.vdf and edit it with NP++

In the find menu, switch to the replace tab. One at a time, of course, find "doom2.bat" and "doom2 + mouse.bat" and replace both with "base\dosbox.exe" without the quotes. (see pictures)
Note: I use "base\dosbox.exe" to keep it the same format as Ultimate DOOM and Final DOOM.

Make sure to just save and not to save as another file type.

Self-explanatory, exit Steam and open it again.

You should now be ready to enjoy DOOM II with Steam overlay (Screenshots, broadcasting) and launch commands!