Alright, so your superimposed lines are looking good. The curves and stuff are less accurate, of course--but you'll gain experience to remedy that. Your ghosted lines are fairly good for the mostpart. There's a bit of wobbling, but it's minor. Hitting the point every time with a perfect line is something to shoot for, but remember that smoothness comes first, and accuracy second. The lines on your ghosted planes are smoother, and that's good. I notice an odd few, though, that are REALLY curvy. You might've had your arm at the wrong angle. Remember you can rotate your page and yourself as well, in any orientation you need to get a smooth line. I know for a fact that drawing lines and stuff at angles we're not used to is insanely hard... at least, for me it is.

Your tables of ellipses are surprisingly well-done. I see a lot of people on this site with really wobbly ellipses but you've managed to avoid that here, so good on you. With some experience, your brain will begin to develop little subtle strategies, and that should help you out with drawing through your ellipses, because some of them are a little bit messy in that regard.

Now, you didn't need to draw two more pages of planes for your ellipses in planes, but more experience never hurts, so nice work there. The ellipses themselves are fairly well done. A few bad apples, though--again, you might've just been drawing at the wrong angle for these. But you did well on drawing through your ellipses here.

The ellipses in your funnels look alright--they're smoothly drawn and pretty accurate--but many of them are angled a little wrong. Make sure to have your ellipses line up together with the minor axis. That'll be important later when drawing cylinders. You did succeed on making them wider as they stretched further outward, so that's good.

Finally, the boxes. Your plotted perspective is done well, though it is missing a third panel. Your rough perspective boxes have some good smooth lines, and they're pretty accurate to their vanishing points too, although there's a page missing here. Your rotated boxes look okay, but they do seem to vary a lot in shape, and the linework is a little messy so it's hard to really see much of it. This exercise is pretty hard, of course, and if you give it another try, I recommend making it bigger. More space helps a lot in clarity when it comes to art. That's why we've got 4K canvases, you know?

Your organic perspective boxes are done well. The foreshortening is a little too extreme on a couple of them, though. Something to remember in this exercise is to vary your foreshortening, but not TOO much. Closer boxes have more foreshortening, while farther boxes have less. And remember, of course, that each plane has a vanishing point they all converge towards very slightly.

So, yeah, if you do believe you've gained enough experience, you can give the 250 Box Challenge a shot. If this were an official critique I'd only let you pass if you did the missing bits, but you've managed to complete MOST of the lesson and you've understood the lessons themselves well, and I'll say that's good enough. The Challenge will give you plenty of practice on the box foreshortening and stuff I was talking about.