I wanted to post some impressions on this one.
It's not as much a game as it is an environment to play with. You have the option to add any number of things to the mountain range itself by selecting various icons at the bottom of the screen. Depending on the icon the effect will either be the addition of grass, various plants, add-ons like trains, clouds and so on. The vid shows far more in the way of what does what than I can go into without writing a short book. (You wouldn't want to spoil the experience anyway) Suffice it to say kids will love it, but depending on your mood it may not be something you want to mess with after seeing everything once. If you like building houses and environments in The Sims you may want to give it a shot.