Thanks for the other feedback!
I personally like the solved wording.
Also another vote for clearer colors about possibility state - for example, the cells are marked green if that specific answer is internally consistent, but it can still be an incorrect solution overall, which means you did not get the correct answer whatsoever.
I think people (myself included) have been trained to think green = good, meaning that answer is correct and shouldn't be moved, you found that one, now work on the others - so an intermediary color as mentioned, like yellow, meaning 'yep that's plausible but not necessarily right' would be a good fit there.
Similarly, "How many questions have E for the answer?"
All the months have 28 days, but people usually answer 1, so for those of us who are used to approaching questions, especially logic questions, as literally a as possible, all the questions have the answer E. It's just not the right answer. "How many questions have E as the answer?" would clear that up for me.
I did accidentally pull down too hard on my screen when I was trying to scroll up, which accidentally refreshed and deleted all my answers on all difficulties, not even just the one I was working on/hadn't solved yet, so that's less than ideal. I almost had level 4 done, but no way I wanted to go back and redo it all!
I'd also love an "answer lock" button, and/or floating undo/redo buttons, because sometimes to take the next step, I need to put in an answer and game out how the rest of the puzzle comes together with that answer, and it would help to be able to undo back to that point, not just try to count my steps and keep scrolling down to the undo button for more of them. I'm not likely to get out a piece of paper or pop open a notepad app to game it out that way.