There's two games similar to that that I know of (though you're probably thinking of the first):
* https://en.wikipedia.org/wiki/Lose/Lose - Each alien represents a file on your computer. If you kill an alien, the game permanently deletes the file associated with it.
* https://psdoom.sourceforge.net/ - a hack of Doom where each monster represents a running process. Kill the monster, kill(1) the process.
* https://en.wikipedia.org/wiki/Lose/Lose - Each alien represents a file on your computer. If you kill an alien, the game permanently deletes the file associated with it.
* https://psdoom.sourceforge.net/ - a hack of Doom where each monster represents a running process. Kill the monster, kill(1) the process.