Thanks for playing! One of the goals of the game was that people who don't know baseball could still find enjoyment in the gameplay, so we're glad to see so many non-baseball folks interact with our title!
As for the graphics, as stated in the entry we use Morph3D base human models. These are available through the Unity Asset Store. The models at highest quality have an incredibly large number of vertices, so instead of presenting them at the highest level of detail we use the lowest level available. This gives a more blocky feel to the character. Next, we wrote our own custom unlit vertex shaders that simple color the vertex with a solid color. We made materials for each component of the person (hair and body) and simply swapped out the provided materials from Morph3D with our own. This same strategy was used for non-human components like the table and background decorations.
Thanks again for playing! Hope we answered your questions.