Puzzle #41 - Mostly Empty Rooms (Heyawake)

I've been attempting to work backwards through every pzv link posted on Twitter for a while now, and over the past month there's been a lot more Heyawake than normal. This is a genre that I used to not understand at all, and though I still don't totally understand it, I'm competent enough to solve and by extension, construct.

puzz.link interface

It turns out, making Heyawake is pretty hard! I've got a few more of these coming, but no Heyawacky (same rules but far less restrictive on puzzle layouts).