Difficulty score 40. I could have used the Nishio technique, but I found a way to reduce it to a couple of alternating inference chains.
Did it, no green, one wrong guess. Real easy otherwise.
The Nishio technique means, if you're making a guess, make it in a binary cell. Pretty much everybody knows that. It's named for Tetsuya Nishio, anime artist and author of several books on number puzzles. Interestingly, and appropriately, it sounds like "ni shi yo," meaning "emphatically do two." Kind of appropriate.