You’ve accomplished exactly what was asked from you for this assignment. Your objective was to simplify a photograph’s color palette and you’ve done just that with gradients of brown with small black highlights.
However, I think your composition could be a little stronger. So far most of your photographs (with the exception of the squirrel) have been taking in 1 layer of depth. In this example, you don’t have a foreground, middle ground or background. All of your action is compiled into 1 layer which gives the image a slightly flattened and dull look. You don’t need to play with a lot of space to create layers. Look at your speaker photograph for example. Simply by changing your perspective and altering your depth of field you were able to provide the illusion of depth. This helps make your photograph more engaging and dramatic.
Shooting within 1 layers isn’t always wrong, but once you start to experiment with layers and depth you’ll soon realize the importance it has in strong compositions.
Similarly, from a composition standpoint, your main subject was a little too centered. Again it’s not always wrong to use formal balance in a photograph, but by abiding by the rule of thirds (informal balance) you’ll likely find ways to make your images more appealing.
Other than that; great photograph. Keep up the good work!