Related: Grey Hack is a fake OS, Network, Internet in a multiplayer game where the objective is to hack (including each other). It simulates many basic functions quite well (you can steal files, place files on other computers, install software, run commands from a command line, including imitations of many tools). You can also write your own programs.
When will someone go all in and release a hack game with hundreds of emulated real little servers of various operating systems and vulnerabilities?
It would be fun to run in an “anything goes” type setup. Get a cheap raspberry pi and install some really old Linux kernel with plenty of well know holes. I’d worry about delineating between game-machines and real ones. It would have to be totally isolated from the real network I guess.