The game is great and generally plays very well. Hugh Allan does seem to develop the best MahJong games on both iOS and MacOS, but he is not good at keeping the games current as the OS evolves. However I do see some significant bugs in the game. For example there are some tiles that incorrectly get matched to tiles that are not identical. This error appears to be consistent so you eventually can learn these mismatches. I have played other Mahjong games by Hugh Allan and this bug is not in those games. Another error appears if you restart the game while a hint is displayed. The game seems to place the "hint" tiles under the main board.