The lines for the shapes look good! They're very smooth and clean.
Also, I'm glad to see you gave the exercise a shot and that you enjoyed it! 
Buuuuuut, if you finish early, try doing it again and think about ways to extend the time. Could you spend more time measuring each part? Did you analyze it after drawing the lines to see if there were any differences before adding the shading? Did you double check with the video to make sure you were doing the steps right and that the shapes were accurate?
And don't forget the main part of the exercise, not moving on until the quality it the same as the previous session. I think the second set is similar to the first one you did, but the next three are a little wonky compared to the second set. In that case, try drawing only three again until they look similar to the two you drew in the second set.
If the quality in very last one you drew looks different or not as good as the very first one, then try to look over your process and slow down.
It's good that you made shadow on the last one darker, but you can see the proportion and nostrils are off and the lines/shading aren't as smooth.
You don't have to get to 5 in one hour within a day. Try spreading it out and do a couple of hour studies one day and then try for four thirty minute studies the next day.
Below I made a tutorial to help you with the shading. I also added the time stamps to see the process and how slow I went.
Hope this helps!
