so what is spacechem? i've heard the name before but I don't associate it with anything
http://www.spacechemthegame.com/about
It's really tough to explain, it is a design based puzzle game, you design these tracks of sorts that elements ride on? It's required that they leave the correct way, in order to get them to that state, you have to combine and bond them among other things... Watch the 2 minute video on that page.
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Indie game board: http://www.gamefaqs.com/boards/293-indie-gaming