Based on the user reviews of "Twelve: The Hardest Puzzle", here are three pros and three cons: **Pros:** 1. Challenging and addictive puzzles that stimulate the mind. ("The puzzles are mind-blowing!") 2. Beautiful graphics and minimalistic design provide a calming atmosphere. ("Beautifully designed and easy to use.") 3. Constantly updated content keeps the game fresh and exciting. ("New puzzles regularly added, keeps it fresh!") **Cons:** 1. Some puzzles feel randomly generated, becoming repetitive. ("Too many feeling like the same puzzle...") 2. Lack of in-app hints or explanations for difficult levels. ("No help or hints, too frustrating.") 3. Limited social features for sharing progress or competing with friends. ("No sharing or leaderboards, not social enough.") Note: These conclusions are based on a snapshot of user reviews at the time of my knowledge cutoff. Opinions may vary as more reviews are posted.