The save files are typically held in two places on our computer, within the saves folder inside the main gamefolder but also in %appdata% , so you should be fine to delete the current game folder completely and unzip the new one in the same place. You can also just unzip the new folder in a different place and nothing would require deleting. Your saves should automatically show up, if they dont you can copy the saves folder over from the previous game. Hope that helps,let me know if you run into any issues.