Mini Fortress writes:
"Tappingo unleashes a simple concept upon 3DS owners, though it’s not always as clear cut as it sounds. There is plenty of challenge to be found in the game, similar to the challenges found in Picross and Sudoku. Tappingo is more similar in concept to Picross in its use of numbers to form an image, though the challenge can be compared to Sudoku. Some lines are dependent on lines created before them, which is somewhat similar to the number elimination process you go through in Sudoku."