Ed Allard, Senior Producer for Popcap, was kind enough to answer some of my questions about casual games via email:
How have casual games evolved since the days of Tetris?
In a way, the games haven’t changed that much at all. The best casual games of today have a lot in common with Tetris – they have simple approachable mechanics, relatively low production cost, extremely wide appeal, and are insanely addictive.
Beyond that, there has certainly been some growth in the overall presentation of the core mechanics. Production values are increasing, which means better graphics and sound, longer game play, and on-line features such as high scores or user-contributed content. One key trend along these lines is the movement from abstract presentations of shapes and puzzles to strongly-themed presentations with real-world (or imaginary) characters, objects, and places. Many have simple stories that carry you through the game and provide a sense of progress and achievement.