Casual Game Design: Designing Play for the Gamer in ALL of Us
"Gregory Trefry defines the attributes for casual games in his book "Casual Game Design" as follows:- Rules and goals must be clear.- Players need to be able to quickly reach proficiency.- Casual game play adapts to a player's life and schedule.- Game concepts borrow familiar content and themes from life.I believe he has made a good approach in trying to define common aspects in casual games."--Gamasutra.com