Yeah, software fullscreen is default.
It's on the table to change the default to windowed. NaOH suggested this 7 years ago already, I had been reluctant, but I'm starting to believe windowed is better as a default. Screens are huge these days, it's perfectly fine to start the window bigger than ye olde defaulte of 640x480.
Hardware fullscreen is a fallback option for Ramond, he wasn't able to run software fullscreen.
Tenmicu (from twitch) had trouble with software fullscreen, he got only a black window. He claims that he has an odd computer and trouble with other games, too. Stilll, this is another reason to start windowed.
-- Simon