In World of Goo, you use physics to build towers which then topple over strategically to solve puzzles. For instance, you might build a tower which will fall to create a bridge over which your goo balls can travel. The core mechanic is great fun, but it's the attention to detail that makes the game shine. Sound effects and music are fantastic. The goo balls let out cute little squeaks and the soundtrack creates a sense of drama. Every level is filled with surprises and new goals you must achieve to succeed. And the satire evident in the light story elements are the cherry on top. To round out the package, you can compete indirectly with other players to build the tallest tower in a sandbox mode.