SpaceChem's omission is probably just oversight. The SpaceChem page itself makes a similar offer, with the same link to Zach's e-mail: http://www.zachtronics.c

SpaceChem's omission is probably just oversight. The SpaceChem page itself makes a similar offer, with the same link to Zach's e-mail: http://www.zachtronics.com/spacechem/ http://www.zachtronics.com/spacechem/ A fun anecdote from a GDC talk (https://archive.org/details/GDC2013Barth https://archive.org/details/GDC2013Barth at 21:57): U.K. schools: We want to use SpaceChem to teach programming familiarity. Eastern European schools: We want to use SpaceChem to teach problem solving. U.S. schools: We want to use SpaceChem to teach chemistry.