What "hard" means here
The hard run is about planning. It mixes every shape, mostly four-tile ones, on the most walled course of the day, and the later rounds need three or four moves each. Every round still stands alone: play each one in the fewest moves and you land on par. Finding those fewest moves is the hard part.
The shapes are drawn fresh every day, weighted toward the square, T-shape and L-shape on this tier. Each round on the par line needs at least as many moves as the round before it, so a run always ramps up.