Prior to SpaceChem, Zachtronics released several freeware games, including The Codex of Alchemical Engineering, the predecessor to SpaceChem, and Infiniminer, the game that started the "block game" genre.
We've also developed a few educational games focusing on STEM topics, including mathematics and biology. They are available for iOS and Android tablets as part of the Amplify Curriculum.
On the Zachtronics podcast we go behind the scenes of how indie games are made and interview other game developers.