Alpha Halftone
Pixy effect generates alpha based on the luminosity so you can easily composite multiple layers over and over, here is one for the highlights and another one for the shadows, etc.

Simple Controls
Control the size and color of the shape the space between shapes or even contrast in size and opacity of the shapes, you can also use the original layer colors and make every shape pick one color from the original layer colors.

Invert the used shade to get the effect you want, you can halftone the shadow, highlight, or the mid-tone, you can also contrast their value.

Original image color
Using the original image colors to generate a retro game style, or playing with the shapes option get more like comic crazy style all done in real-time and with a single click.