Whenever you purchase an app it saves under your Google Account, as long as you have that Google Account, resetting your phone to factory settings won't stop you from getting them again.
Your game progress won't necessarily be saved, though. It depends on if the game backs up its data to your Google account, or to its own server. If all of the data is locally stored, then you'll lose that progress. You could consider backing up your app data using Helium, before you do the factory reset.