I had to switch to a new system, because I'm above the 4GB limit Itch.io has on uploads, so it's possible there's a process issue. I'll get it fixed as soon as I can diagnose it.
Weird; I just downloaded it on my side (win64), and it unzipped cleanly. Are we talking about love-of-magic-book2_win64.zip or love_of_magic_book2_0_6_17c_win64.zip? What unzip package are you using?