Edit (03/05/2022): My friend coerced me to replay the game the other day. It appears past wrongs have corrected themselves, and there is now a bordered window mode in the game.
I was playing the game Raft with a few friends a couple of years ago. It was fine, but I found myself wanting to idle in-game do other things every now and then in other applications. The only problem is I couldn’t move the game to the side or arbitrarily resize it. Bringing up other applications and changing the z-order of the windows was pretty much all I could do. I couldn’t find a built-in feature to window the game, and there didn’t really seem to be any working suggestions, even though other people had expressed this problem in the discussion boards.
In response to this post, I made a PowerShell script to grab the application’s HWND and makes the game resizeable and moveable with a title bar. The Pastebin can be found here.
There’s not too much to it, and it can be used for any app and any combination of window styles with a few changes. Sharing with PowerShell is nice because it comes standard-issue on Windows OS and allows people to see the comments so instructions can be added, and people can see there are no malicious shenanigans within it.
PowerShell has a few tedious issues because a few security settings need to be set up first (explained in the script comments). Still, you don’t need to worry that a layman needs some other prerequisite scripting environment (e.g., Python) installed or have them run a stranger-danger executable (*.exe).
Even if you’re not playing Raft, it’s still a decent reference on how to modify window styles in PowerShell using wrapped Windows SDK calls.