They look fine to me also. They are clean, simple and recognizable. As you gain experience you will be able to progress to more intricate portraits.
As DW said, the pattern is a guide, and can be adapted. With the intricate portraits I do I often have to make adjustment for the fact that I am using 'spiral blades' so I don't destroy some of the finer details. I may extend a particular cut or even eliminate it completely depending on wood, blade, pattern and my ability.
Usually once the pattern is removed even WE won't know that the change was made.
One other suggestion is that you do your portraits in a STACK!
I never cut less than 2 thicknesses of wood just so I have better control of the blade. My current project is a portrait of a large 'feline' and my stack consists of 1 -1/4", 2 - 1/8" BB and a 1/8" piece of Sandeply as the backer and potential 'throwaway'. I am now at 120 cuts and should finish today with about 45 more cuts and I have had to do a LOT of 'creative cutting' to make all the details come together.
~~~GB~~~