I loved the original Jar of Marbles, and this is an awesome step up. It's the same game at its heart, but feels like a much richer experience. The art is beautiful, the sound compliments it well, and all-in-all, the game has a great atmosphere.
The gameplay is generally easy to understand, and the physics-based nature of the game makes for a challenging experience. It's sometimes frustrating when a marble rolls somewhere you didn't expect, but often times that leads to an even more advantageous position.