Here's a hint for the reference just 3 letters from the title and make a word

I don't get the reference, but my goodness it's like night & day this version and V1. The old one just looks plastic and/or like nerf guns, and just stick out like a sore thumb from TF2's artstyle with the heavily saturated colors. The gold highlighting is much better, and looks like actual highlighting instead of just a lump of bronze or gold-imitation plastic/rubber. Green texture: same story; ambiguous, looks kinda like it might be plastic paneling, but more industrial/high-quality instead of cheap kids toy. The most improved is the purple texture. Man, it just underwent a total transformation. I must commend you: you did good! This gets an upvote from me.

Is this a reference to EVA or something?