The reviews don't appear to have experienced the same app or are biased (in my opinion) because there is nothing 4-5 star worthy within this app.
While this claims to be a memory game app, the way it is setup when you first open it leads one to believe otherwise. There are lists of "codes" you must choose from then enter that code on a separate screen before you can begin to play.
You have the option of 2-4 players...doesn't appear to be for single player. In addition, the game doesn't progress, you can select the same two tiles over and over without progressing the game.
Poorly constructed app. Save yourself the headache and download something else.