Here in codeofaninja.com, we usually have three LEVELS of source code output. But WHY? Because I believe in "Learning Progression" to ensure efficient learning.
Not all of us can swallow a lot of information all at once. So we do it one at a time. By different levels. This way, learners will be forced to learn the essential basics of the subject.
Accoding to Dr. W. James Popham, an Emeritus Professor in the UCLA Graduate School of Education and Information Studies:
"Learning Progression is a sequenced set of skills and knowledge we believe students must learn on the way to mastering a more distant curricular outcome."
You can read more about the subject here, here and here.
So if you really want to learn, and serious about learning from our programming tutorials: I highly recommend studying the LEVEL 1 source code first, then the LEVEL 2, then the LEVEL 3 source code.