Off the bat I can say your boxes are super clean. Lines are straight, without any notable wobble or repeating lines, and even when adding lineweight to the outside edges it looks clean and confident. So do the hatching lines. Great job on this regard.

I could only find the red lines in box 81 extended in the wrong direction (remember they should be extended away from the center of the initial Y), which shows you have good comprehension on this aspect, since extending lines in the right direction wasn't really an issue.

Convergence was clearly the biggest struggle for you in the beginning, but I can see noticeable improvement around box #50, when lines seem to meet correctly more consistently, specially with more extreme convergence. It's mostly in the first pages where you can see some divergence and parallel lines (which were more constant til' the end but I consider they are less of an issue).

There's a few pages where the orientation of the boxes looks somewhat similar, but for the most part they're very distinct. Don't be afraid to rotate them constantly to practice drawing them on varying angles.

As for most, the inner corner seems to have been a bit of a challenge for you, but you seem to have grasped good control over it with practice. If you ever find yourself struggling with it, try changing a little bit the order in which you finish the box. It seems to help most people.

Overall I'd say the progress you made during the challenge is evident, and I think you're more than ready to take on Lesson 2. Good luck!