The hatching effect was achieved by using a texture that is being sampled based on the screen position.
Have a look at this impressive Unity-powered hand-drawn shader, created by Developer and Programmer known only as Mr-Dev and showcased via Reddit. Currently WiP, the shader in question was set up using the engine's Compute Shaders, allowing its creator to give 3D meshes a stylized toony look. According to the developer, the neat hatching effect seen in the demo was achieved by using a texture that is being sampled based on the screen position.
"I'm not quite finished it yet and I would like to use it for one of my own projects first, but after that, I might consider releasing it in some way. If I do, I will make another post here," commented Mr-Dev.