: This indicates it is the 9th piece of a multi-part RAR archive. Understanding "Develop Piece"
If you only have part09 , you cannot run the game or see its contents; it is just one fragment of the complete data set. Serious_Sam_4_v1.09-Razor1911.part09.rar
: You only need to right-click the first file (usually .part01.rar ) and select "Extract Here" using a tool like WinRAR or 7-Zip . The software will automatically pull data from all other parts, including part09 , to create the final usable folder. : This indicates it is the 9th piece