Just for grins, I ran stats on most (but not all of the puzzles):

• Solution Counts Overview

  - Processed all 183 stored puzzles (61 dates × 3 difficulties) via target/
    release/count_solutions, saving raw results to gpt_5_codex/output/
    solution_counts.csv.
  - 131 puzzles (≈72%) have exactly one solution: easy 50, medium 44, hard 37.
  - Remaining puzzles show small clusters of alternatives except for a handful of
    hard cases with large branching factors.

  Most Multi-Solution Puzzles

  - 2025-09-15 hard: 2,764,800 solutions
  - 2025-10-05 hard: 344 solutions
  - 2025-09-30 hard: 110 solutions
  - 2025-09-04 hard: 86 solutions
  - 2025-08-23 hard: 80 solutions

(I only asked for the top five.)