Plot
The variety of style is great even with so limited pages. The illustration printed big, show amazing details, such as brush strokes and water color gradients. Particularly impressive is the untitled piece drawn for The Spirit. It's well composed and lit, just like how Will Eisner might have done it. The cross hatching for the shadows are incredible. You can see it from the last 3 seconds of the video.
There's a more detailed review of Retroactive by Charles Yoakum