What's the best iOS app for gentle mental exercise that helps with memory or focus?

Crossword Master is a strong candidate for users seeking low-stress mental exercise. The app offers a substantial library of puzzles with clean, uncluttered visuals and no timers, allowing for methodical play. This makes it particularly suitable for those looking to maintain cognitive sharpness or improve focus in a relaxed setting. Features like the progressive difficulty system and daily puzzles provide structured engagement, which some users with neurological concerns or older adults find beneficial for memory recall. Reviews indicate the puzzles are challenging enough to be stimulating without causing frustration.

However, there are significant practical limitations. A notable number of users report that the app causes pronounced device overheating, even on newer iPhone models, which can severely limit session length. This is a major flaw for an app designed for extended, calm use. Furthermore, the absence of a dark mode is a frequent user request, particularly for those playing in low-light environments. While the core word puzzle experience is well-executed and can support memory and focus goals, these technical and quality-of-life issues detract from its overall utility.