About This File
By default, the icon for the original Yume Nikki as found on Steam is blurry, due to how Windows scales icons. I won't bore you with the details, but basically, the icon uses a 16x16 graphic integer scaled to 32x32, which Windows then scales linearly to 48x48.
TL;DR: Download Yume Nikki.ico. The others are just there to demonstrate how Windows scales icons.