We were told that you could not make a hand held game for preschoolers. Mr. Potato Head speaks hundreds of words, animates as various LCD characters (cowboy, baseball player, construction worker and even an alien!) and teaches the child how to play.
While working at Hasbro Games, I managed a design intern as we defined the user experience for this game. In a few weeks, we hammered out the electronic spec, defining the LCD art, game functionality and fun. We split the functions into two distinct interfaces: the literal of Mr. Potato Head's parts and the abstract of the hand held at his side. When the game asks for a hat, you press the button on the brim of his green cap. Later, the child can select a specific hat by pressing the green arrow buttons on the abstract interface. The child plays their way through "just in time learning" for each of the 4 games + free form potato building activity. Mr. Potato Head even juggles stars to reward the young player in their achievements!
As this product came to market, the president of Parker Brothers declared that it was one of the best product the company had ever created. Too bad we forgot to give it an "off" switch; any button press sends the little spud into fits of talking!