Scientist (Evolution)
From Valve Cut Content
Our favorite Science Team had gone through many iterations until the looked like we see them today.
Version 1: Concept Art
The earliest version of the scientist. He has clothing different from any of the models, resembling more of a spacesuit than a lab coat. This version has round pitch-black glasses, which survived in the next version.
Version 2
The second version.
Version 3
Scientists getting beaten by HECU
The models looked very similar to the previous version, but unlike the previous iteration, it does not have the same amount of "bloodiness" on the textures. "Walter" model's glasses had become more blocky, similar to what we have today.
This article about evolution of a subject could be expanded.
