Wow, these are excellent. I love the light value across the eyes in the first image.

This layout looks very organized. The grid paper works great for this.

Very nice 👍

Very cool tank! The spaces between the wheels are filled in with black. This is a great stylistic choice but it makes it hard to evaluate if these are correct cylinders. I can only see one plane of the wheel cylinders: the ovals facing us. And I think you have the major and minor axis reversed on them. I would suggest uploading one more attempt at this exercise and not erasing the construction box that you use to draw the cylinder. That way we can help you improve or validate that you have mastered this lesson.