[Five minutes of... is a series of video game investigations by Margaret Robertson, former Edge magazine editor-in-chief and current development director of social game studio Hide&Seek. Here, she explores what five minutes of play reveals about a particular video game, this time focusing on the elaborate, difficult-to-play and surprisingly thrilling PC title SpaceChem.]

There are stories you tell that you shouldn't tell. I've got a great story I tell a lot -- inspiring, funny, life-affirming -- that I shouldn't. It's a story about why I believe creativity is important, and about why I believe making things is hard. I could tell it here, but I won't, because it's largely about pooping, and it turns out that pooping stories are the stories that you tell that you shouldn't, even when they're great.

Instead, let's talk about SpaceChem. It's a game I realize I don't know the genre for. A blueprint puzzler, maybe? Its heritage is in Pipe Mania and Deflektor and The Incredible Machine, and you might have last played one in Train Yard.

In SpaceChem you configure the inside of a series of chemical reactors. A configurable system of circuits moves atoms about, bonding and breaking apart molecules, reconfiguring sequences of substance.

Your tools are pretty restricted -- broadly speaking you can pick things up, break 'em or bond 'em, and dump them in the output -- but the combinatorial possibilities are clearly colossal.

What the game asks you to do with these tools is the impossible. It's a long time since I've played anything so astonishingly dispiriting. Each level teaches you a new insight, and then the next level presents you with a problem which is in no way solvable with that insight.

Instead, it gives you a spatial, procedural and logical task which transparently exceeds the tools at your disposal. But you've come this far so you sit and chip away, and fail and flounder until you happen upon another insight, which unlocks for you a next level that is in no way solvable with that insight.

This, now that I've written it out, probably doesn't sound like the five most thrilling minutes you might hope to experience in a life well lived.

But, of everything I've played -- with the possible exception of an incident involving Alien Trilogy and a poorly-secured poster -- I suspect SpaceChem gives me the strongest readout on heart-rate spikes and coritsol levels. I've played Resident Evil 4 hooked up to skin conductivity detectors and can tell you with total confidence that it's got nothing on SpaceChem.

The five minutes balanced on the fulcrum of finding a solution are as exquisite an emotional roller-coaster as you could ask for.

The first prickly suspicions that you're close to an answer are actual physical sensations, sweeping up and down your body. There's a slight surge of panic as you worry that your optimism might jinx it, a tang of fear as you anticipate the crushing pain of yet another failure.

Hope builds as one, two, three, ten molecules hum harmoniously off the production line. The elation that follows is an actual endorphin rush. I'm not sure I've ever taken the idea that your heart could literally swell with pride seriously before, but there is a warm bigness in my chest that wasn't there before.

And, then, you get to share that glow with your rivals, your mentors, your pupils. It's likely that if you're playing SpaceChem you'll have all three, and that they'll all be embodied in the same people. It's a game that's hard to play alone, partly because once it's under your skin it's hard not to proselytize, and partly because before it's under your skin, you're unlikely to make much progress without some one-on-one tuition.

Your solutions are exportable as video files, and it's impossible to resist the urge to send them on, as tokens of gratitude, answers to questions, implicit gauntlets.