To run version 1.6, the game requires at least 70 GB of SSD space and a 64-bit Windows 10 operating system.
Large games are often split into smaller "parts" (like part04) to make downloading easier and avoid file size limits on certain platforms. Cyberpunk.2077.v1.6.GOG.part04.rar
The .rar extension indicates a compressed folder that requires software like WinRAR or 7-Zip to extract. To run version 1