How many people are playing SpaceChem right now?

SpaceChem has 7 players on Steam right now, with a 24-hour peak of 21 and an all-time peak of 866 on Jun 2014.

What is the all-time peak player count of SpaceChem?

866 concurrent players on Jun 2014.

SpaceChem was released on Steam on 2 Mar 2011.

From the store page

20 achievements

Chief Executive Officer

Junior Permutation Technician

Environmental Engineer

Industrial Physicist

Materials Engineer of the People

Junior Performance Specialist

Performance Specialist

Performance Specialist II

Senior Performance Specialist

Efficiency Specialist

Only the achievements the store page highlights. The rest follow once this game has been read from the achievement schema.