This is a very easy thing to do, and most people probably already know how to do it, but here it is.


Step 1 - Go to your Steam Library
Simply hover over the "LIBRARY" option at the top of your screen and click "HOME".
Why did I even include this step?

Step 2 - Enter the Local Files
Put your cursor over "Commander Keen Complete Pack" and right click on it.
Hover over "Manage" and another menu should appear.
Click on "Browse local files" and you are now in.

The game already contains DOSBox, but it is an old, outdated version, so we will replace it with the most recent one.


Step 1 - ..downloading it
Go to this link: https://www.dosbox.com/download.php?main=1 and click on the big green download button, which will take you to SourceForge. When there, simply wait for the file to finish downloading and then run the executable.

Step 2 - Installing it
Once you run the executable, you are met with a huge license agreement, which you have to read before clicking "Next >", as if people ever read these..
Tick the "Desktop Shortcut" option if you want.. well.. a desktop shortcut of DOSBox.. and click
"Next >".
Then, select which directory you want to install DOSBox to and click "Install".
Once it's done, click "Close".

Step 3 - Messing with the Settings
To get to the settings, you have to go to the directory you installed the game to, for me, the directory is "C:\Program Files (x86)\DOSBox-0.74-3".
After you find the directory, double-click the batch (.bat) file named "DOSBox [version number] Options.bat", which should open a Notepad window.
Now, it will obviously be different for everyone, but I suggest you leave all the options the same, except for the "scaler" option, which looks best at "normal3x".
After you have made your changes and are satisfied with them, close the window.

DO NOT PUT ANY MOUNT LINES, NONE OF THE GAMES WILL LAUNCH

This is the final part, so don't worry, you are almost done.


Step 1 - Replacing the Executables
Hover over the DOSBox executable (Be careful! Not the shortcut, the executable!), right-click it and select "Copy".
Now, go back to the local files and copy the executable to all five folders (base1-base5). It will ask you if you want to replace the old executable, say yes.

Step 2 - Deleting Unnecessary Files
Finally, go to each folder again and delete the following three files:
dosbox.conf
dosbox-0.71.tar.gz
keen[number].conf

Done!

Didn't I just say it was over? Well.. it is.. this part is just for those who like being incredibly specific.


Step 1 - Removing the Shortcuts
The old shortcuts do work.. but do not get along with icons. No matter what icon you throw at them, they will all spit out the same error: "The folder 'C:/Users/grayson.EDEN/Desktop/Keen for Steam\[number] - [game title]\[number] - [game title]' specified in the Start In box is not valid. Make sure that the folder exists and that the path is correct.
So, select them all and get rid of them.

Step 2 - Making New Shortcuts
Select the batch (.bat) files "Keen 1-5.bat", right-click them and select "Create shortcut".

Step 3 - Adding all the Icons
Right click each and every shortcut you just made, click on "Properties", click on "Change Icon...", click "OK" to make the error message go away, click "Browse..." and find the icon (.ico) files of each game.
Each icon file is inside the "base" folder of each game (for Commander Keen 1 it is in /base1/keen1.ico/, for Commander Keen 2 it is in /base2/keen2.ico/, etc.)
After finding the icon you want, double-click it, then click "OK", and then "Apply", you can then close the windows.