1) This is only important if you are using Galaxy, Windows 7 and want to have a working overlay in Galaxy.

According to the gamecard the game officially should support Windows 7 and provides overlay achievements ect. Unfortunately out of the box this is not the case. To even launch the game you need to add the launching parameter -dx11 since the game defaults to launch in DirectX 12 which is (normally) not supported in Windows 7. Adding this parameter will launch the game. However if you are using the custom parameter feature in Galaxy you will lose the overlay.

I contacted GOG support about it and they said that the fact that the game does support Windows 7 does not have to mean that Galaxy supports it as well. That's imo complete nonsense from a legal point of view since you will find not a single line about this on the gamecard so the customer will expect that the game will work on Windows 7 without any problems - including Galaxy because those Galaxy features (including overlay) are also mentioned on the gamecard. Anyway - at this moment I am not sure if GOG even plans to fix it so I decided to fix it by myself. I edited the config file for this game and sent it to GOG so that they would not need to figure out how to fix it since I already did. I also decided to offer this solution to everybody who would be interested in it.

Here is how to fix the issue:
1) Download the edited file "goggame-1585377690.info" from here
https://drive.google.com/file/d/1wXhtpf24qpogYc5BhQ_K02oGQxvF8fhn/view?usp=sharing
2) Close Galaxy.
3) Rename the original file which can be found in the installation folder.
4) Copy the downloaded file into the game directory and start Galaxy again.
5) It might be that the game now is not listed in Galaxy anymore. Don't worry. Simply click on the cog icon on the left side in Galaxy and chose "Add game & Friends" -> "Scan Folders for GOG Games" and point to the directory in which you have installed your GOG games. Galaxy should say "1 game imported" and show Observer again.

If you now want to start the game simply click on the symbol to the right of the "Play" button and chose "Additional executables". Here you will find "Observer System Redux DX11" which will start the game and keep the overlay working.

If you prefer to use the "Play" button only, you need to do one additional step: Click on the symbol right of the "Play" button and chose "Manage Installation"-> "Configure". Scroll a bit down in te window and you will find two entrys below of the checkbox "Custom executables" - one of those is set as "default" via radio button. Simply chose the other one. Now, since this argument is set to default, it is the one that will be used whenever you press the "Play" button and overlay will still work.

Keep in mind that a future update will change your config file again. Also it is important to note that the config file also contains the ACTUAL build no. So of you archived the file and you want to use it again after an update you should use the actual build number from the updated version and put it in your archived file - otherwise Galaxy will still think that the update is pending (thanks to Hustlefan for bringing this to my attention).

I really hope that GOG still will fix this in the future so consider this to be a workaround for those who still use Windows 7 and Galaxy and don't want to wait.

Edit: Since GOG has now fixed the issue this workaround is not necessary anymore.

Thanks so much for taking the time to explain all of this. It is much appreciated.

I dont like using galaxy so I downloaded the fame in offline mode for windows 7 and I am having the same issue where the game tries to run with dx12. I cant figure out how to run the game with dx11

It is much more easy with the offline installer version. Just open edit the shortcut made by the GOG installer and add the paramter -dx11 to the executable line.

thanks, I figured that out already but if it were not for your post, I would not have know to put -dx11 on it. thank you.

You're welcome, glad you can enjoy the game now :)

Actually Marko you should REALLY NOT remove the file!
Please preserve it for legacy purposes for those who may choose to play non-current version of the game.

So somebody would want to play a non current version on Win7 - very unlikeley, but you are probably right and options are always a good thing. I will put it back on but people will have to take care about the build number as mentioned in post 1 by themselves (so far I have updated them the moment GOG released another update). In the recent reelase GOG has taken the build number out of the info file so it is not needed here anymore but if you want to play an older version you still would have to change the build number in my file to prevent getting update notifications.

Well... There is me :P It's not particularly relevant that I don't own REDUX specificly atm. I personally don't particularly care about "most newer version" - older versions are a usefull thing for things like speedruns.

If you want it preserved then upload it to PCGW (of course you would need active account there).
Obviously add as much info (such as exact intended version) as possible ;)

I have already reactivated it. The file is so small that it does not bother me to keep it on my google drive :)

Right. But you would get uncomparably more exposure for the file by adding it to PCGW (where people often go looking for fixes, which is not some obscure forum cough GOG cough).

Feel free to do so if you want. I just wanted to help the GOG community as long as it takes GOG to fix this mistake and yes, I do expect the GOG comunity to look in the forums. I don't think that it is really worth investing more time in something that has already been fixed but do with the file whatever you want if you see this different.