Felix the Cat Spot the Difference

Spot the Difference game where character of whole number 23 of Felix the cat appears. The tap is done and the part where a right and left picture is different is answered by using the flick operation of iPhone.
It is possible to advance by starting from level 1, and answering four questions or more in five questions of each level correctly at the following level, and 150 questions in total are prepared for a super-difficult problem level 5.