I think that Angry Birds and World of Goo only work because of their freedom. Chess, Tetris and DROD work because they are beautifully simple and discrete. Mine

I think that Angry Birds and World of Goo only work because of their freedom. Chess, Tetris and DROD work because they are beautifully simple and discrete. Minecraft took a "mathy" world to the extreme while AAA games seem to explode in organic freedom. Cut the Rope uses a physics engine but enforces "one right way" through its level design. Maybe it's not so black and white, but rather designers make parts of a game discrete until it becomes simple enough to be fun. Whatever it is, the complexity of this game concept feels overwhelming to me. It's a bit like this physics-based Tetris, I would try it for fun but only for free and for five minutes.