"The Battle of Bunker Hill."
Doing these comp studies at a small size forces you to ignore all the details - the minor separations of tone, the individual handing of each soldier, narrative details like the drummers, the bodies strewn about- and focus on the organization into large shapes. Most of the soldiers are organized into a big block. We can see the sheer number of people as it goes back in space, across the lit area in the midground. The large, simplified light and dark shapes are broken up by contrasting accents to add interest, something I'm starting to see more after reading a quote by Pyle's student, Harvey Dunn-
"Lick touches of light into the shadow field to give zip to the points of interest in the quiet tones and to tie the light field and the shadow filed together, similarly put a few flicks of dark in to the light field."
One of the most useful composition principles that we learn is to put the area of highest contrast your focal point. Note that it applies to much more than value- the highest value contrast we see here is in the background, with the dark smoke silhouetted against the white cloud. That's not where we first look, though. The focal point is on the soldiers in the foreground, where the tiny light, dark and red shapes form a pattern, contrasted against the economical shapes in the rest of the piece. Even more importantly, this is the area of the highest human interest. Unless you're doing something very wrong, a person will look at those areas first, not necessarily the point of highest value contrast.
As far as shape language, what I see most is the ordered, geometric shape of the soldiers marching forward, to meet the dark and looming, chaotic shape of the smoke from the battle. The contrast between order and chaos is the heart of the idea here. Note how perfectly in formation all of those soldiers are. I'd reckon that the vast majority of painters would try to ham-fist some "visual interest" into the scene by breaking up the poses in that formation. The rifles wouldn't all be straight; the light shapes formed by their legs and cuffs wouldn't all line up so perfectly. In Pyle's piece, he's at once staying true to the reality of how a military formation would have looked, and is emphasizing the idea of complete order and discipline, in contrast to the chaos of everything around them. We can almost hear the drum beat and the noise of battle, from the dark smoke cloud, and from the other bodies lying about- the ones nearby contorted, and the ones farther up the hill so strewn-about that their red uniforms make it look like a blood stain on the battlefield. That makes the main soldiers' bravery and discipline marching forward all the more incredible.
This one's another Pyle painting on Jekyll and Hyde. I couldn't pick out much from this one aside from, again, seeing how well and simply the light, dark and middltone shapes are organized. I did find one fun bit though.
The shape of the foreground guy's hand silhouetted against the light jumps out immediately, so it's obviously important. Look at how that shape is mirrored in the painting on the wall... and check out the sharp-angled shape of a beast's mouth about to bite it. Right there, that gives you an idea that Jekyll's about to turn into something quite dangerous. You don't need to know the story behind the painting to see it.
EDIT: I'll need to go back to studying that Jekyll/Hyde painting sometime. One of the risks of finding cool things like that painting on the wall is that it becomes easy to overemphasize the role they play. I thought about it a little and removed it in Photoshop to see what effect it would have. I don't think the piece suffered at all. Clearly, it's not as crucial to how we perceive Pyle's painting as I first thought. Lesson learned: always test your conclusions.