Looks good! The mountain image certainly draws you in.

I wonder whether the white header element could benefit from a thin rule, or small shadow to give it depth when content goes under it? Especially where there is text on the white background.

Very impressive — especially like the # of +Z stats

I made the jump to Javascript from Actionscript (which is similar) but found the best to get way to get started was to visualize my code.

So, for example, I'd experiment with placing squares on a canvas. Then, I'd randomize the color of the squares. Then add a click handler to them, and so on...

As others have mentioned though, just starting and writing some code is the main thing.

Deconstruct the most simple of examples and move on from there.