Can you add a license file?
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So I can take it and reuse it exactly as is and claim it's my own and sell it on Steam for $60 a pop?
So I can take it and use your name that is surely somewhere in the code and fill it with swastikas and hate speech and say that this represents your views?
Or more reasonably since I don't see a license this is copy written reserving All Rights and anything said here is just a trap you're just waiting for me to do something cool with it then hit me with a lawsuit and take my money, right?
But more seriously head over to the open source initiative read up on a couple of licenses and pick one. Almost any license will prevent people from using your name but let other people use the code if that's a thing you want.
If you just want to protect your name and let people use the code for whatever even making money consider an MIT or BSD Style license.
If you want (to protect your name and for) other people to be able to use the code but need to share their changes consider a GPL style license. This will complicate other people making money but doesn't strictly prohibit it.
If you don't want (the previous stuff and for) other people to be able to prevent people from selling it you might want to use something like a Creative Commons non-commercial license, I won't be perfect but there are flowcharts you can follow to figure out which license works for you.
That has nothing to do with the game being free. If you dedicate source code to public domain and someone slaps swastikas on it, it doesn't represent OP's views all of a sudden