Starting with your form intersections, while the intersections themselves are mostly coming along okay despite a few errors, my bigger concern is with the actual linework itself. I'm seeing a number of missed ghosted lines, ellipses that are somewhat uneven or misaligned, and some lines that show a bit of hesitation in their execution. I've noted out a bunch here. This is definitely something that will need more attention from you in your warmups.

As for the intersections, the arrows I noted down on that page show the curvature of the form's surfaces. When drawing the intersections, this is what I try and think about. You are getting there though - for example the sphere-box intersection at the top of the page was handled incorrectly, but you did handle the same kind of intersection at the bottom of the page much better.

The last thing to mention on that front is that you kind of jump back and forth between more appropriate, limited use of line weight (just focusing on clarifying specific overlaps) and being a bit too liberal and tracing back over long strokes. The issue with using line weight that way is that tracing forces us to think more about the lines as they exist on the page, rather than how they represent edges in 3D space, and in turn that flattens things out. Limiting line weight to just shorter segments, and drawing them confidently using the ghosting method ensures that they blend smoothly back into the existing strokes (as explained here). These concerns about line weight apply to the rest of your submission as well, though I won't be beating a dead horse.

ANYWAY. Moving onto your actual object constructions, your work here is for the most part done quite well. You've shown a great deal of care when it comes to subdividing things to a very precise degree, finding all the specific locations for each of your smaller forms, rather than approximating it more arbitrarily. I also noticed that you tended to keep your constructions boxy with lots of sharp corners, until the very last step when you rounded them off. That is exactly what I want to see, as it results in much more specific, believable, and structurally sound curves that exist in 3D space.

My only concern honestly comes down to your ellipses. Now, ellipses are definitely challenging to be sure, but yours are definitely coming out quite loose especially at larger scales, which suggests that you might not be drawing them from the shoulder, and/or may not be as consistent or conscientious about applying the ghosting method to them as you ought to be for each and every mark you draw.

When I say ellipses are challenging, I do mean it - I don't expect students to be able to freehand ellipses perfectly at this point, and from this lesson onwards I allow and encourage the use of ellipse guides in order to avoid having students get distracted from the core purpose of each lesson because they're too caught up in the mechanics of their ellipses. It is understandable that you'd still be freehanding them in this lesson though - full ellipse guide sets can get pricey, and most students opt instead to get a 'master ellipse template' which puts a wide range of degrees and a few different smaller sizes on a single sheet (meaning that they're much more limited in the sizes you have access to). All that said, definitely try to get your hands on one for the 25 wheel challenge and lesson 7. Despite the small size they'll still be usable, and it'll be hugely beneficial.

Do of course continue to practice your freehand ellipses in your warmups - the ellipses in planes and funnels exercises will be quite useful in refining those skills, but at the end of the day, being sure to use the ghosting method and to draw from your shoulder will be integral.

Aside from the points I've raised here, your work is honestly coming along very well. I'm especially pleased with the handgun - the barrel's probably a little short and the grip/trigger guard probably got a little stretched out, but despite these proportional issues, the construction as a whole still came out feeling very solid and believable due to how you stuck to your guns (pardon the pun) and kept trucking forwards without attempting to hedge and backtrack to correct mistakes.

All in all, I think you're moving in the right direction, and your use of construction is coming along very well. I'll go ahead and mark this lesson as complete.