There is a game I want to run (I am on debian 4.9) but it is kind of sketch so I want to run it in some kind of emulator so it thinks it's the only thing on my machine so it can't delete my files or upload them to somewhere. If it's mining bitcoin or putting me in a botnet or whatever I don't care really as long as it only does that when the game is running. (When I close it it stops and it doesn't start except when I start it.)
I was thinking of just setting all my read permissions to me only and running it under another user, but I'd also like to be able to use my computer and files like normal while it is running, so this isn't really a great solution.
Also ideally I don't want this to lag out the game too much. How do I do this?