[KaktoR]

Oh ok, so this is actually warez (we aren't allowed to talk about warez, nor sharing it here apparently).

In this case I missunderstood you. I thought the bin files are actually part of the game itself. I looked on steamdb depots for this game and there aren't any file types in this case so I was confused. Now I understand.

Ok so, then this bin/arc archive should be a part of an installer I guess, which contains the actual game files just compressed (like we do if we creating repacks).

The problem now is, that you can't compress this already compressed files further to achive a better ratio. First you have to extract the archive (the game files) and then apply better compression on them to gain a better ratio, simple said.