The app can download files that aren't labeled for a platform, and trying to run them will instead open a directory. The only issue right now is that the app is built around the idea that it only "installs" one file per game. So you may run into some trouble if you have a game combined with some extras. The next version of the app should hopefully make this better, but in the meantime you'll have to direct people to open their download page in their browser to be able to download everything.