It's not obvious to me the developer was using a 3D library! It looks like this was made in 2010, and uses and SVG library and vanilla Javascript. https://github.com/bwhmather/missile-game
The flash game it's based on does have more textured walls, although overall shading is still pretty minimal. I don't know what 3D flash development was like.
The flash game it's based on does have more textured walls, although overall shading is still pretty minimal. I don't know what 3D flash development was like.