Skill Trees in Education

I looked over some of the programming tutorials recommended by Hour of Code and found that they taught the material very linearly, even if the subject material was very divergent. I thought of the "skill trees" that some games have and imagined how they might be applied to education. Instead of having to go through every detail that the writer of the course thought was interesting, the student could start with the critical infrastructure and then get presented with an array of paths from which to choose.

Suppose a student just finished learning the syntax of a programming language and how to make it do basic IO. He should then get to choose which to pursue first: file handles, rendering, classes, or whatever else you can do with basic understanding of programming. Even better, for a computer science course, things like binary and networking could be unlocked in parallel to programming.

With skill trees, students could see their progress split into a huge sprawl of new things to learn and see how all these interesting skills work together. Perhaps some experimentation or studies are in order?