Regardless of other reviews, this game challenge you with each and every game. I have played just about all other mahjah games, but this game is better than any other mahjah game. Yes there are ads, but more time to playing. No time or score to distract you, just relaxing fun and mind sharpening skills. Each level (9) offers a different set of puzzles. Never the same one. I dare you to play the complete nine long mind blowing games. Very well constructed.