Windowkill is a fantastic twin-stick shooter, where the game window is constantly shrinking on you and enemies spawn across multiple windows. It's truly clever and now it has full customization available via the newly introduced modding support.
Read the full article here: https://www.gamingonlinux.com/2024/04/the-ridiculously-fun-windowkill-gets-modding-support-with-a-source-code-release