Fun fact revealed in a GDC talk: Even Zach Barth himself did not feel motivated to complete the final SpaceChem level. He just designed it to the point where i

Fun fact revealed in a GDC talk: Even Zach Barth himself did not feel motivated to complete the final SpaceChem level. He just designed it to the point where it "looked solvable" and then turned his playtesters loose on it. ( https://archive.org/details/GDC2013Barth https://archive.org/details/GDC2013Barth at 19:20)