Hi Senpai i am trollfromhell and i am gonna give u my critique for your finished exercise

1.lines

your super imposed lines are fraying on both ends and i think u should take time for ghosting before u stroke ur lines but ur ghosted lines are really good

2.elipses in planes

make sure when u draw elipses u draw it through twice and use ghosting method to estimate your elipses also keep the lines of elipses close together and it takes lots of elipses to be draw to get clean looking elipses 

3.tables of elipses

just keep the lines of elipses close

4.funnels

 the minor axis (the line in the middle) should cut ellipses in 2 symetrical halves.

5.plotted perspective

they look really clean and neat i like it so much you are doing a great job

6.rough perspective

your width and heights lines are great!!! they are perpendicular to the horizontal line

7.rotated boxes

i see some of the boxes are not rotating but i guess it's okay because this is your first time to face drawing in perspective like this so i reccomend u to check this out if you wanna get good at drawing rotated boxes https://cdn.discordapp.com/attachments/368870697742630912/715669112222908466/zfr3o7xneog31.png

8.organic perspective

yes these boxes look great because the perspective is not too extreme so it's still easier for the viewers to look at the rotation of the boxes,good job

u should move to 250 boxes exercise