Hey mate!
This is indeed a very good lesson for alternate picking
And you are already on your path with doing a great job, but as Gabi said, you need to work on your hand synch a bit more. Please slow down the lesson and make sure that both your hands are in perfect synch and the timing is correct and then, maybe record against the original lesson, to notice the eventual differences.
I would totally recommend you to take a look at this lesson as well:
http://www.guitarmasterclass.net/ls/Picking-Hand-Basics/It deals with basic picking in the context of various rhythmic subdivisions - it will help out a lot
Also, if you wish to develop your AP skills further, please let me know and send me a PM!
Cosmin