Microsoft Word let's me just save a file and it doesn't ask to overwrite it if it's the file I picked for saving the document or if it's the file I opened to open the document. The game should also not ask to overwrite an existing save to the same file I saved two ten seconds earlier or to the save file I used to open the game. Consider a "save" and a "save as..." option, like in ordinary software, so it's more familiar to users and I don't get pestered about saving every time.