I noticed that neither the 1.3.1 nor the 1.4.1 installer allows directory selection during install, it only asks whether to create a desktop shortcut and then proceeds to dump the files into C:\Kerbal Space Program, completely disregarding whether there is an existing installation there or not. I wanted to install the game into a separate folder on my SSD (which is not the C: drive in my case), but for some reason the installer doesn't feature such basic functionality and the links to zipped versions at Store are all broken.