For those bothered by the long download times, trying later may help, at least until loads of other people start trying in the afternoon, & then it might become faster in the morning. ;) Just before noon I was looking at 6-7 hours -- around 1:00 pm it took 6 minutes.
One comment said that unchecking the option for Full Screen caused a black screen -- I can verify that, & I had to use Alt+Tab to close the game. Editing the options.xml [under Users\ [UserName]\ AppData\ Roaming\ Alawar\], changing true to false for fullscreen, worked. Right clicking the game's .exe file, selecting Troubleshoot compatibility also worked -- it said it set compatibility for Windows 8.