Hi there sterben, good call on getting official critique before moving on. There's a lot to go over here so let's get to it.

Overall the theme here is going to be confidence, or rather your lack of it when it comes to executing your marks. Your super imposed lines are very wobbly showing that you are drawing slow and trying to steer your pen rather than working on getting swift, confident motions down. Right now we need to focus on flow, and accuracy will come later. The same can be said for your ghosted lines; make sure you are ghosting of course, but also that you are using that shoulder to drive a confident fluid motion.

With your ellipses the same can be applied although it is definitely harder to do with ellipses than lines. Using your shoulder and ghosting in an elliptical motion is tricky at first and takes a lot of practice. With your ellipses another big thing is tightening up those draw through passes, which ghosting will help with as well. With your tables of ellipses you did a good job keeping things packed together to reduce ambiguity, and by the end your ellipse are starting to get tighter. Your ellipses in planes however are very messy - even your planes are very haphazard, or dare I say, rushed. Make sure you are taking your time with and ghosting every single mark you make. Your ellipses are not making contact with the planes appropriately, as described here so watch out for that. Your funnels exercise shows some glimmers of success with bisecting the ellipse with the funnel axis, but for the most part things are still very hapharzard and sloppy here.

With your rough perspective boxes you are doing ok at keeping your vertical lines perpendicular to the horizon and horizontals parallel to it, resulting in proper orientation for 1 point perspective. Your converging lines are also on track and as you practice more, your accuracy to distant points will improve. The big thing here is once again lack of confidence/ghosting as most of your lines are wobbly.

Good job pushing through and finishing your rotated boxes. The only goal for students here is to finish it so they can be exposed to new types of spatial puzzles and solution methods, so mission accomplished. As far as where to improve, first of all I think you could have drawn larger. Drawing larger gives your brain (and arm) more room to work through these spatial puzzles. Your lines are looking a little better here but you have a lot of redrawing of lines which can make things messy/visually cluttered so try to stick to one mark unless you're adding line weight in which case you should be ghosting and preparing to lay down a line right on top (think super imposed lines exercise). You have the beginning of rotation going on but mostly you're skewing your boxes over so they are not rotating. Watch this gif again and study how the rotation is driven by the motion of the vanishing points along the horizon. You were hit and miss when it came to keeping your adjacent lines close to each other to leverage as perspective guides. Overall, this was a good attempt and I'm happy with it.

Finally let's look at your organic perspective. Your sense of scale is really nice here. You have a clear fore, mid, and background established by the sizing of your forms. This is a key strategy in creating the illusion of 3d space on a sheet of paper. To further push that illusion you could have overlapped your forms more as that causes the brain to interpret these forms to all exist within a single cohesive space (similar to keeping foreshortening of your forms all the same). Your perspective is starting off ok and as you continue practicing your sense of converging lines will improve. Overall a good start here.