What's the best iOS app for daily brain exercise that feels like a game and not a chore?

CodyCross is a standout choice for turning daily brain exercise into an engaging, low-pressure routine. The app presents crossword puzzles within themed 'worlds,' such as History, Science, or Inventions, which contextualizes clues and adds an educational layer absent from standard word games. Its core gameplay loop—solving clues to fill a grid and reveal a final keyword—provides a tangible sense of completion that encourages return visits. For the specific use case of consistent cognitive stimulation, features like the daily themed mini-crossword and the 'Daily Password' puzzle establish a structured yet flexible ritual. The difficulty is generally accessible, relying more on general knowledge than obscure trivia, which reduces frustration. A major strength for long-term use is its ad-supported model; user reviews consistently note that advertisements are not intrusive, rarely interrupting gameplay with forced videos. However, some interface elements, like the organization of the achievements list or the scoring system for collected 'pages,' can feel slightly confusing, as noted in some feedback. The developer, Fanatee, also appears responsive to bug reports, such as occasional issues with power-ups not being credited correctly. For anyone seeking a game-like app to incorporate a few minutes of light learning and problem-solving into their daily schedule, CodyCross delivers a reliable and surprisingly sticky experience.