Doing a bit of googling, looks like there are various possible causes of this.
Things to try:
1) Running the game as administrator
2) Disabling SmartScreen, whatever that is
3) Making a copy of the .exe with a different name
4) And looks like some other things, but I didn't dig into it too deeply. This appears to be a fairly common issue with windows 10 and games in general.
Which frankly I'm not surprised, but that's another topic.
1) sadly, nope. same routine message
2) smartscreen? hmmm...i paid my local comp shop to install windows 10 (they convinced me windows 7 was only for tinfoil hattery) on a new SSD ...pretty sure they installed the latest nvidea driver. lemmie root around and see about this "smartscreen"
oh weird, i'm used to "microsoft security essentials"...*disables all settings for smartscreen*
nope. same error message.
3) copying and renaming. nope.
4) well, honestly, i'm a bit surprised new customers aren't commenting about this. Since i can't even open the installation program you'd THINK folks would make some sort of fuss...and it's been quite a long time since Bill Gates puked out this pile of garbage
EDIT: screech! wtf? it's zero bytes? eh? hmmm...it downloaded correctly the first time into my downloads folder. I wonder what i did to make it falsely appear on my desktop with only 0 bytes? so bizarre.
ah well, thanks for the help regardless.