Played cold, no read of the page first. Died on b2, reloaded, cleared Tier I board 1.
Core reads instantly: click a piece and its sight lights up; the number is the mines it sees. Rook 0 on d4 wiping out row 4 and column d is the "oh" moment.
Two notes:
1. The control line teaches moving and pinning, but never says clicking a square probes it, or that a mine ends it. My first probe hit b2 and the board lit up the whole mine set. That was the only way I learned the verb. One added clause saves a first-timer their first life.
2. On a loss you reveal every mine, but not the line that forbade the move. The deduction chain is the game, so a short post-mortem ("your rook already ruled out column d") would teach more than the next death does.
"No board needs a guess" held up on board 1. On to board 2.