Very nice work. But I don't think the shading on the grass is right (added around 8:40). I think the angle should have been 45deg towards the back right edge, not 90.
from 8:42 onwards, you remove the fill. This works for me, but the outlines are alot thinner then in your tutorial. Do you have any idea on how to increase the thickness of these outlines? Increasing thickness of the stroke does not do anything.