The original copy is better than your proposal: you get to the checkmate point, which is the essence of the captcha, at the very end. The way it was originally

The original copy is better than your proposal: you get to the checkmate point, which is the essence of the captcha, at the very end. The way it was originally laid out, it's clear that you are looking for checkmate in one, while in your copy it seems acceptable to click any black piece.