BowTieBuck here o7,

All of your drawings exhibit a strong sense of three dimensions through effective use of cast shadows and texture around the silhouettes. They also follow the constructional process.

Some areas of improvement to make this post feedback:

Shrimp: Though a preference, I would construct the tail as a sausage form, rather than individual spheres connected in a curve. A sausage creates a clear boundary for the silhouette whereas spheres leave a dip of 'empty space' that needs to be imagined when you add details later. Put another way, the sausage gives your mind contours to follow when adding the shell segments; sphere chains do not.

Bee: Good use of the fur texture around the silhouette of the bee. I would suggest varying the shapes and sizes of the tufts, into large/med/small groups for visual interest.

Generally: It is somewhat difficult to see the underlying construction with the opacity lowered. While visually it looks better that way, these are exercises and construction is exactly what we are interested in critiquing. Lastly, I suggest trying these exercises using the fine-liner that Drawabox suggests, even if just to appreciate the difference in media.

That said you demonstrated the necessary skills to pass lesson 4. Keep it up!