Ok, so I love maths and machines, but this is pure beauty. You build a system which converts water and CO2 in methane and the molecules literally dance. I'll say this: it's a puzzle. It's a very fine crafted puzzle without time constraints. That's the basics, so if you like this type of games, keep reading. If not, Spacechem is not for you. The very gem of this game is his sandbox approach: except of the 'big boss' puzzle, you can do WHATEVER YOU WANT. You have some starting chemicals, and you have to manufacture some others, and for doing it you have some tools. Whatever you do with those tools is up to you. You could build a very fast process with a lot of symbols (instructions), or a very efficient one with a few symbols but quite slow. You can hack a solution inefficient and slow to advance and then revisit the old level to refine that solution with fewer symbols and less cycles. It's like the incredible machine but with the incentive of going back to rebuild your past levels in a better way. And the push to do it is presented to you after every level: a comparison with the other players in terms of reactors, symbols and cycles used. Isn't it enough? You have an entire library of custom levels to hone your skills (once you prove yourself worthy... or hack your access). If you like it, you won't run out of puzzles, that's for sure.
