The information is for smart phones and tablets. They say that the pleasure level was highest for about 3 minutes per scene or level change and 15 to 20 minutes of game play, regardless of how long the total game time actually can potentially last.
For example, many games allow the player to advance levels quickly if skilled and also play a game for 30 - 60 minutes ( or more in some cases ) depending on design, but the pleasure or satisfaction level was highest as stated. The survey implies that a game has a greater chance of popularity and replay if the game designer takes the data as a guide and minimum. Allowing the player to advance too slow or fast diminishes the end user satisfaction on average , ending the game sooner causes disappointment , and requiring the player to last longer than 20 minutes loses some customers .
Interesting that the data triples for computer games, simply because being at the computer implies that the end user has more time to play.
I read the information on the World Wide Web, but don't remember the source - some video game industry website of some kind. I'll try to find the source in my data base.
[Edit:] One solution mentioned was to allow continued play at a later time, one time only.