Definitely do not need all that junk ^ This was all done on Windows 11 and working great. Start with a clean game install and uninstall junk if you already junked it up. Will all work the same on Windows 10.
This is heavily worded to provide as much understanding and step-by-step as possible. Once I'm done with the game, this is done and I won't add anything further (am now finished).
See especially H to fix some crashing issues should you see them. See C, F, and K for other workarounds and issues on crashes. Anyone might see these. The crashing issues are not from the following junk free way of doing things. You can fix the broken video playback (mpeg error) 1. Remove ALL compatibility options including admin on the OVERSEER.exe (right click on it > properties > compat). This will fix the no playing videos issue (unable to activate mpeg2 failure). If you need to, click change settings for all users, untick, save, untick all now. Even using admin can cause this failure to show so uncheck that (using admin for a game especially is also a bad security practice). Various GOG games will see issues like this that are default enabled and are solved by disabling compat options (something they didn't realize when they did it).
2. On game start select use ffdshow.
You can make the videos take up the full screen width 1. Create a shortcut to "ffdshow.ax" in the game folder (right click on the file and find "create shortcut") and setting its properties target to example "C:\Windows\System32\rundll32.exe "C:\Program Files (x86)\GOG Galaxy\Games\Tex Murphy - Overseer\ffdshow.ax",configure" and then run it.
2. ffdshow.ax. Adjust aspect ratio if wanting to do that by checking resize and simply choose "resize to screen resolution". This helps to remove black bars from all sides of videos and fills up the screen. Its much better.
3. Also enable deinterlacing by simplying checking that one box while here as on heavy video movement this removes the lines and makes it look much better.
4. You need not do anything else but play the game. However, your own adjustments to settings in ffdshow config can be made. Another way to affect it is the ddraw.dll fix below and where you can resize using "DisplayAspectRatio=display".
You can fix the green and multi tiled videos by 1. Create a shortcut to "ffdshow.ax" in the game folder (right click on the file and find "create shortcut") and setting its properties target to example "C:\Windows\System32\rundll32.exe "C:\Program Files (x86)\GOG Galaxy\Games\Tex Murphy - Overseer\ffdshow.ax",configure" and then run it.
3. ffdshow.ax. Down towards the bottom of the vertical menu: Output > Uncheck yv12 and OK to save and exit.
If getting the transparent filing cabinet issue that you can see immediately on first gameplay At least for Nvidia, this is an Nvidia color issue on the cabinet's texture so it doesn't get rendered and a ddraw.dll workaround is required. Personally, I don't recommend the one others have used above.
1. Just grab
https://github.com/narzoul/DDrawCompat/releases (under assets at the bottom of a version) will be a zip (do not grab the debug or source ones). There's one file in it and no config is required to use it. Just unzip and put that ddraw.dll into the game folder where the exe is. Its very easy and works great.
A. One downside is that the video aspect ratio fix above to remove black bars from all sides won't fully help anymore (but do still use it). One solution to this is to create a new empty file in the game dir "DDrawCompat.ini". Copy paste into it w/o the quotes "DisplayAspectRatio=display". Save and play. This will stretch and fill the monitor with both videos and gameplay. I
very much like this and won't look further into this.
Some other issues. A. For in-game midi music, make sure its set to midi in the midi list in audio settings. If its empty see G below. You
do not need to download anything for this.
B. If subtitles blink during videos, uncheck captioning in settings to stop the blinking.
C. Crash at the cabinets in the attic. It won't crash when you use the correct key to open it so just use it when you have the key. This isn't a game blocking issue as there's ways around this. See F and H for other info on the crashes. Make sure to clear out "AppData\Local\CrashDumps" at times as the crashes do add up over time.
D. Error box on transitions. Happens when you don't have A. set correctly. Has to be set to midi.
E. If you have a quick blink of black screen when trying to start the game but it fails (this is a crash), this can be a conflict situation, such as if you have k-lite installed for another game. Uninstall k-lite (or whatever) and it should start.
F. The cog wheel puzzle (see H for actual fix). Going to be a bit annoying. Use the puzzle. Wait for it to crash. It creates an emergency save here. Start the game and use the crash continue button. Click on the puzzle. Repeat until the emergency save is able to save after the dialog. Its close so you should get a good emergency save in about 1-10 times of this. You can continue on the puzzle once the save has passed the dialog. Good to clear out "AppData\Local\CrashDumps" after this. This last test took it 10 times to do it. If you don't use the crash continue button then forget ever getting past it this way. This issue will have caused wrong solutions to be present on the internet as people will randomly pass it thinking the solution is then correct and not properly confirm.
G. If the midi list is empty in the game audio settings then you have the game files messed up such as ffdshow.ax. Try deleting that file and verify the game. Using mute can also do this: Unmute, exit settings, return to audio settings and it will no longer be empty.
H.
To fix the crashing after Tex talks (see K for in-game crashing) Choice 1. The crash is related to paths/location in some way. If I run the game from "C:\Program Files (x86)\GOG Galaxy\Games\Tex Murphy - Overseer2" which is a direct copy from Choice 2 and not previously used then the game crashes during the cog wheel puzzle. It still does not have any issue at "C:\Tex Murphy - Overseer" even after this test. Moving it one dir down to "C:\Program Files (x86)\Tex Murphy - Overseer2" also sees no crash. Moving to "C:\Program Files (x86)\GOG Galaxy\Tex" sees no crash. Moving to "C:\Program Files (x86)\GOG Galaxy\Games\Tex" has no crash. "C:\Program Files (x86)\GOG Galaxy\Games\Tex - Tex" has no crash. See I (lowercase: i) below for a path with a different issue.
Choice 2. If you need to reinstall the game and possibly to another path. This is the initial way I got it fixed. I reinstalled directly to a USB HDD to example "D:\Tex Murphy - Overseer", where it was fixed and then copied to root location on NVMe "C:\Tex Murphy - Overseer" and its still fixed. With the new install, copy in the two save game dirs "games" and "players", the ddraw.dll, and anything else. Make the adjustments needed before starting the game to the OVERSEER.EXE. Start the game, load, select the profile, load the save. If all went well, you should be crash free.
I did not rule out other path related issues. Its likely that I won't finish the last little bit as you can definitely easily enough fix the problem from this info by simply moving/reinstalling the game folder location and adjusting shortcut path or whatever way you want to go about it.
I. If launching the game fails and the mouse is stuck in a small invisible box on the screen, this is a path related issue and it cannot launch. Happened on "C:\Program Files (x86)\GOG Galaxy\Games\Tex Hello World - Overseer". Change the path to whatever like "C:\Program Files (x86)\GOG Galaxy\Games\Tex" where the game starts fine.
J. ffdshow.ax config can act weird and not show up if you manually move the game dir from the original install location. Re-add the ffdshow.ax file and a shortcut to the original location to be able to once again bring up the config.
K. Alcatraz in-game crashing. Crashes should stop around cell block D. Crashing while moving around that happens near the end of the game at Alcatraz. I did not look into this. You can get through this despite the crashes. Just have to deal with the crashes and is good to clear the CrashDumps folder after this as it can add up a lot here. Can minimize the crashing by using a walkthrough to get through it easier and faster.
Alcatraz loading may also have world anomalies after loading. I only had this happen one time and loading the last save did deal with it.
That's it. Fully playable to the end. 
