The Player Points feature is sort of like the high-score screens of old arcade machines. Developers can implement systems to award points to players for achieving certain goals in games.
To view the current player point rankings for a particular game, visit its details page and click the Leaderboards tab. Here you can choose to view the rankings for today, the past week, the past month, or of all-time.
For more information on gameplay and building related matters, please check out the following links: