This game is absolutely incredible. In about 10 minutes I've done a bunch of 3x3s and a 4x4 to see how it works with black squares. I'd encourage you to tweet this at the Wordplay / NYTGames accounts and to make lots more of these!
Actually, a little feedback:
- on my iPad the bottom row of a 9x9 gets clipped in a way that makes it very difficult to play https://imgur.com/a/EpSPiz1
- Some clues reference 14-across or 16-down or whatever, but I don't see the numbers in the squares / a full list of clues to compare with.
- I wish tab took me to the next clue and space changed me from across to down.