Thanks for the high praise, Justin. No custom shaders here. I just changed the color of the one light source from white to red using an AnimationCurve. The objects in the scene only reflect their red components when the light source is purely red itself. So, anything made of only some amounts of green and blue looks black. I set the ambient light to black. The surfaces are not quite purely diffuse (there actually are faint shadows, if you look closely). There is no skybox. The sky is just a fill color. One little trick I’m pleased by is that the sky goes from black to white when the lightning flashes, but in between black and white you can see it has a red tint. That’s done by using the same AnimationCurve to set all three RGB components, but first squaring the G and B. So, when the curve value is zero, R=0, G=0x0, and B=0x0 (all zero), and when the curve value is one, R=1, G=1x1, and B=1x1 (all one). But anywhere in between, like one-half, R=0.5, G=0.5x0.5, and B=0.5x0.5 (R=0.5, G=0.25, B=0.25), so there’s much more red.
Your game is pretty amazing itself. Terrific animations.