Summary: I want to like this game so badly, but I'm stuck in the beginning levels, only barely introduced to multiple reactors (multiple of the puzzle screens connected in one level, to make more complex results). I made it through Braid and Portal and a bunch of similar games. This is just above me. It's worth trying (the demo), but expect to fail if you're just an average person like me.
Summary: This game really makes no sense to me. I've done the tutorial numerous times and I can't seem to grasp the key elements of this game. I only played it for the Team Fortress 2 items and I wont be playing it again.
Summary: Amazing puzzler. Discover your own solution. Completing a level is a challenge, perfecting your designs for speed and efficiency adds replay.The tutorial instructions are a bear, but with a bit of experimentation and rereading, it makes sense. Stick with it and you will love it. I haven't read a wink of the story. NOTE: You can delete entire areas if you click drag a selection box and press delete.
Summary: The level of difficulty on this game is sick! It starts out fairly easy, but it gets hard fast. Seriously, your brain will start to hurt with infinite ways to solve each puzzle as you ponder how to design a more efficient solution. One-click YouTube upload for easy solution sharing. Such a simple concept, yet so much innovation in this absolute must-have indie gem--so addicting.
Summary: I'm a computer science student, and people have often wondered why I enjoy coding so much - well, SpaceChem is a good example. It's not really analogous to coding, but it has the same mental effect, uses the same parts of my mind that coding does. This is easily one of the best, and legitimately difficult puzzle games I've ever played.
Summary: This indie title is simply designed, but highly complex, and can keep you interested for hours on end. You may even spend an hour or two on many of the stages. There's a lot of tweaking involved here. Though it may seem a bit trial and error, you really have to spend quite a bit of time thinking of your plan before you begin combining elements. Once you've got a workable method, it's down to the tweaking of timing and orientation of your molecules.
Summary: I tire of games that are all about killing, or mind-numbing match-3 games. SpaceChem is fairly original, but most importantly, it's different from 99 out of 100 games coming out today. It starts out easy to get you used to how it works, but doesn't take long to start challenging you. As others have said, what seems impossible at first ("Surely it can't do that *and* that?" - oh yes it can!) eventually comes floating to your head after a good break. I *love* this game!
Summary: SpaceChem has been one of the most fulfilling puzzle games I have ever played. On more than one occasion I've been completely stumped by a solution, stumble off to bed, and dreamed of reactor errors only to sit down at my computer to find the solution in fifteen minutes the next morning. I've been challenged by many puzzle games in the past, but from their very design if I was stuck there was no working around the problem. In a way, they were simply to simplistic.
Summary: This has a linear learning curve, satisfying level design, and even a few bonus rounds and boss battles to excite while remaining strictly casual. The music and sound effects aren't particularly painful, the graphics are functional and smooth. There's also a plot, although interesting and grisly; it doesn't impact gameplay in any meaningful way.
Summary: SpaceChem is a puzzle game that looks deceptively easy. Just moving atoms around and assembling molecules, right? But it get's pretty challenging pretty quickly as the molecules get bigger and the number of bonds increase. It is a hard game to put down and I've found myself pondering certain puzzles long after I closed the game, figuring out solutions in my head and then going to the pc to try them out.