Congrats on going through the gauntlet. It looks like you've already started on later lessons so I'll keep it short.

Regarding your box construction, you do a good job making sure the edges of the boxes converge to the vanishing point. I see improvement as you continued on with the challenge.

Regarding line work, you draw really crisp and clean boxes. I do recommend you integrate drawing boxes every so often in your warm ups and practice line weight as well.

I believe you are ready to continue to the next lesson if you haven't already.