You cannot open or extract part12.rar individually. You must have all parts in the same folder and start the extraction from part01.rar .
Approximately 48.1 GB (compressed from an original size of 158.5 GB). Atomic Heart -- fitgirl-repacks.site --.part12.rar
This part contains a portion of the compressed game data needed by the installer ( setup.exe ) to rebuild the full 158.5 GB game directory. Key Usage Notes You cannot open or extract part12