It looks like you’re dealing with a split archive file, specifically the fourth part of a multi-volume download for . Because this is a .rar part, it usually contains a portion of the game's core data, which cannot be opened individually without the other parts.
: If you only have part04 , you cannot extract the game. You need the complete set starting from part01 .
: Large games like Just Cause 3 (which is roughly 40-60GB) are often split into smaller "parts" (e.g., part01, part02, etc.) to make downloading or sharing easier.