Starting with the first section of the exercise, there are a few areas in which I believe there is some room for improvement that will help you as you continue to move forwards.

First and foremost, I'd say the choice of a bright neon yellow highlighter to identify your correct minor axes was not the best choice. While I'm sure it's a little easier to make out in person, making it unnecessarily harder to see those correct minor axes means that actually learning from the analysis is going to be that much more strenuous. In the future, please consider that just about anything would be preferable - including a pencil.

A second issue I'm noticing is that your straight lines (the side edges of your cylinders) appear not to demonstrate proper use of the ghosting method. You've got loads of overshooting, none of the common signs of ghosting, plenty of places where you're correcting your mistakes (a bad habit that should be avoided, mistakes should be left alone), and many lines that are at least a little wavy. This immediately calls into question just how quickly you may have been working through this submission.

Now, I certainly have no way of being sure (maybe you were working on this challenge prior to getting lesson 5 completed), but all the signs certainly point towards you having rushed through this challenge in the week between the previous lesson being marked as complete (August 13th) and the submission date (August 20th). Perhaps you were particularly interested in getting this out of the way, but whatever the reasoning, not taking the time to complete the work to the best of your ability makes any critique I have to give you considerably less meaningful. I'm sure that had you invested the appropriate time and care into each individual mark, your results would have been vastly superior, meaning that the majority of the advice I have to offer comes down to "don't rush".

The last point I want to raise in regards to this section is that from the looks of it, there isn't very much variety in terms of foreshortening on your cylinders. For the most part they maintain the same overall scale from end to end (sometimes actually getting bigger on the far end in contradiction to the rules of perspective). It's important that whenever you do any exercise like this, as discussed back in the 250 box challenge instructions, you strive to add a good deal of variety, drawing some with shallow foreshortening along with some with more dramatic foreshortening.

When doing so, be aware of the fact that foreshortening manifests in our cylinders in two distinct ways. The one most think of is the shift in scale, where the farther end gets smaller overall than the closer end. The other way is through a shift in degree, where the far end gets wider than the near end.

A more dramatic shift in these aspects of the cylinder suggests that the cylinder is longer and therefore receives more foreshortening. A shallower shift in these aspects suggests that the cylinder is shorter, and therefore receives less foreshortening. If however we look at examples like #130 or #133, we'll see cases where there is a more dramatic shift in the degree (suggesting that they're longer) as well as a shallower shift in overall scale (suggesting that they're shorter). This is a contradiction.

When drawing your cylinders, you need to be aware of what you intend for the cylinder you're drawing - if you want it to suggest greater foreshortening/length, then you need to exaggerate both of those shifts. If you want it to be shorter and shallower, then you need to keep both shifts minimal. The shifts will still be present, just not as much.

Continuing onto the cylinders in boxes, I continue to see suggestions that you went through this section rather quickly as well, and as a result, I don't necessarily think you were analyzing those highlighter lines as closely as you could have. There are some areas - for example, page 28 (cylinders 184-188) where fairly consistently you extended the red lines towards the viewer (although in 187, it's the blue lines that are extended incorrectly, and quite sharply so). As explained here back in the box challenge, the lines are to be extended away from the viewer in order to study how they behave, whether they converge consistently, or whether they actually end up diverging from one another in contradiction to the rules of perspective.

Now, this section of the challenge is actually primarily focused on getting students to develop their ability to draw boxes that feature a pair of faces that are roughly square in proportion. This isn't stated in the instructions themselves - it's one of those things that develop while following the instructions, and I feel making them aware of that fact ahead of time can serve as a bit of a distraction.

The idea follows the same principle as the line extensions in the box challenge allowing a given student to analyze how far off they are from consistent convergences, and to take make adjustments to their approach to shrink their margins of error. By adding the cylinders, we end up providing ourselves with three additional lines (the minor axes and the contact point lines) which will only converge towards the box's own vanishing points if and when the ellipses themselves represent circles in 3D space, given the orientation defined by the box. The closer the ellipses are to representing circles in 3D space, the closer the planes containing them are to representing squares in 3D space.

Now, from the looks of it, you seem to have glazed over some of the instructions and only checked the alignment of your minor axis lines. As explained here, there are three sets of lines associated with each ellipse.

Now, I've written a very lengthy critique for this, despite the fact that the challenge was not approached as instructed. I hope that I have done an adequate job of pointing out precisely why rushing in the way that you did, both in the reading of the instructions and in the execution of the task, is not a good use of either of our time.

I ask that you complete the challenge again, from the beginning, and that you submit it as a new post. That will come with a charge of an additional credit. Please take the adequate time to draw each cylinder, and each and every mark (both ellipses and lines) using the ghosting method to the best of your ability. In addition to this, do not forget the other requirements laid out in Lesson 0 - between the adherence to the 50% rule and your regular warmup routine.