Hiya! Decided to toss a few bucks to get the HD version, but I'm unclear as to how Fullscreen is supposed to work. Is there a key or something I'm supposed to press? I bought the Windows HD version, for clarification.
F11 or alt-enter is fullscreen!
If it comes up surprisingly small still, you might have to go in its properties, compatibility options, and set hi-dpi mode to "application".
Also, thank you! :)