The wording in the page description is rather unclear, so it took me a while to understand what I was supposed to do.
It's fun once you get it, though the UX of pressing escape, moving my mouse to click in the corner and then moving it back to the center to click in the spinbox is way too many steps for my linking. A single key-press to bring up the spinbox and set focus on it would suffice. It would also be nice if the game remembered what your last brick count was every time you wanna start a new round, rather than always defaulting to 2.
Additionally, either I don't understand binary search that well or there seems to be some sort of bug whenever the number of rows is higher than one. Sometimes, only bricks in the same row get destroyed even when higher or lower rows should've broken as well, and from that point on every subsequent destruction acts inconsistently. This is unfortunate given how the game really shines when the brick count is high.
Finally, I'm not so sure this really fits the theme of Forgotten Knowledge. You're not really forgetting or re-discovering what the right brick is, you're learning it for the first time through the method of binary search.