Playing it these days, my first question is always the same: How did I get in? Impossible Mission kicks off with the game's lithe secret agent already safely inside the underground complex, standing in an elevator with no apparent roof access, and surrounded by thick walls of rock on either side. (Dennis Caswell, the game's enigmatic designer, was apparently fairly proud of his rock-scrambling algorithm.)
What's the story? Was there a hatch or a service tunnel hidden by the game's side-on perspective? Did I beam in using alien technology? It feels like a magic trick: I've breached the perimeter, but I can't see how I did it exactly. I'm inside, but I shouldn't be.
That's today, of course, and the question itself only reveals the lapse into unlovable pedantry that has characterised my slow crawl towards adulthood. It's the kind of fixation on minutiae that can only come to mind when you're already balancing weekly shopping bills and council tax, worrying about the plumbing, or ordering books like "Monetary Policy: Fiscal Policies and Labour Markets" on Amazon. (Granted, that book is totally rad though.)
Back then, however - back in the 1980s - the question was always: How am I going to get out? Ahead of me there were dozens of rooms filled with deadly challenges: precision jumps, laser beams, nasty little robots. Survival was unlikely, and actual success was pretty much fantasy: it really did seem to be an Impossible Mission.
Impossible Mission is a game about snooping around in someone else's belongings. You progress through the adventure by searching a series of rooms, a single item of furniture at a time - tearing through bookcases one moment, gym equipment, reel-to-reel databanks and bathtubs the next.
In a game where you have absolutely no aggressive options at your disposal - unless you count putting robots to sleep for a few minutes with the right computer program - all of this hunting and spying still manages to make you feel a bit guilty, and a bit vulnerable. You're deep inside somebody else's house, they know you're there, and you've just found out what they keep in their humidor. I know: it's pretty much the MadWorld of burglary games.
The context provides some decent justification for rummaging around in a stranger's stuff, however. This is a proper evil genius's lair, filled with colour-coded elevator shafts, endless metal walkways, and truly deadly AIs, and your breaking and entering action is all in the name of trying to save the world.
Dr Elvin Atombender owns the place, and he's planning to nuke the entire planet, if memory serves. For once, you're facing a baddie with some quasi-understandable motivations, too: rather than turning to evil because he reckons a chuckle-voiced old cheeser killed his old man (Charlie's Angels), or because somebody flash-toasted Maggie Gyllenhaal (The Dark Knight), or because of, um, copper-poisoning (Speed 2), Atombender gave himself to the dark side when the penguin-heavy computer game he was playing crashed just as he was on the cusp of a really high score.
No room for sympathy, though. As a secret agent, your objective is to root through Atombender's stuff, searching for puzzle pieces that will eventually reveal the password to the good doctor's inner sanctum. Then you've got to put the pieces together. Then you've got to remember where the inner sanctum is.
It's a lot of fun, actually, not least because the game's a beauty to behold. Your secret agent's sprints and tumbles set the standard for animation at the time of Impossible Mission's release, while the sound effects - from the Bacofoil riffling of running feet on steel walkways, to the hubble-bubble technogrumble of the individual rooms, and the endless synthesised taunts from Atombender as you work your way deeper into his lair - were probably never bettered on the Commodore 64.
And beyond that, the setting remains completely fascinating, offering a bizarre clash of the deadly and the domestic as you pass through gantried chambers filled with nippy little robots, giant looming chess boards and fireplaces, arm chairs and old hi-fi units. That by itself is enough to suggest that, if nothing else, Impossible Mission could have been the basis for one of the world's great sitcoms. It's such a shame Leonard Rossiter is dead.
But back then, the game was not remotely funny. As a five- or six-year-old, Atombender's fortress was absolutely terrifying. The jaunty, high-contrast subterranean world was claustrophobic and lonely, its hundreds of nasty quirks and tricks were capable of keeping me up at night long after I'd finished playing it.
The doctor's robots may have looked pretty harmless - in certain colour schemes, they actually kinda resemble Snoopy, which should be frightening only if you've had some very bad experiences with dogs - but they were absolutely merciless as they lasered you to pieces.
A rarity for videogame nasties, they were genuinely intimidating, too, a series of different AI behaviours meaning that sometimes they would patrol back and forth along set paths, while sometimes they would burst into life as you got close, zipping after you far faster than you could run. Worst of all, sometimes they would simply sit and watch you, staring malignantly like large metal frogs.
At the time, their predictable unpredictability was enough to convince me that they were actually aware of my presence, and that they were really thinking about things. And it's probably best not to get into the sheer screaming horror of the weird black ball that floats after you in certain levels. Back then, I didn't realise that it was a pinch from Rover in The Prisoner, but I sensed its malevolence all the same as it hovered towards me: a deadly over-sized Malteser crafted from bile, battery acid and five other different kinds of poison.
None of this was helped by the fact that, true to its name, Impossible Mission is not a particularly easy game. The player is given six hours to root through dozens of different rooms, searching for that nine-letter password, but you're docked 10 minutes each time you die, and two minutes each time you phone a friend for help on your pocket computer. And that's it: when your time is finally up, the world shakes itself apart in a series of brisk Doomsday explosions, and you're left with nothing but blackness and the sharp synthesised crackle of Atombender's laughter.
There are so many opportunities to die, too, either by touching a robot - touching in the literal, rather than the Hallmark sense: robots were a tough crowd even then - getting zapped by lasers, or plummeting to your death with a horrible scream.
Seeing as your agent is the most graceful of early computer game protagonists, it's initially quite a shock to see him disintegrated, or lose his footing and stumble into oblivion. It's clear that he probably wouldn't have done that if he was truly in control: it's clear that, actually, it was all your fault.
Nothing's quite as terrifying as the unknown, of course, and for me, the unknown was Impossible Mission's endgame, once you'd finally pulled Atombender's password together - no easy task, as the puzzle pieces could be flipped and rotated in dozens of different ways - before heading through the bright blue doorway that lead to the doctor's inner chambers for the big confrontation.
I never got that far, actually - I don't think I ever got more than half of the letters of a password, either. Time passed, and many years later I gave in and checked the game's finale out on YouTube. I won't spoil it for you, other than to say that it's nice to see Norman Tebbit was crafting a career outside of politics even then, but I certainly spoiled it for myself.
The excitement about what lay behind that final door had been brewing for the best part of two decades: unless Impossible Mission concluded in an emotional reunion with a choice selection of my own dead relatives (unlikely, given the C64's processing power) it was always going to disappoint.
Playing the game again on Wii Virtual Console, it's easy to appreciate its finer qualities, but I don't feel that same childish terror any more. It makes sense, really: I'm ostensibly a grown-up now, which means I'm meant to fear deadly robots only on special occasions. Perhaps if Impossible Mission focused on negative equity, Multi-Drug-Resistant Tuberculosis or accidentally getting in trouble with the tax people, it would be more effective.
There's something else beyond the waning appeal of the subject matter, though. Games are an imaginative business, in so much as, to really work, they require imagination from their players as well as their designers. I've probably lost a bit of that special power to lose myself in fantasy worlds (my third and fifth wives would disagree with this, however).
That's why I can enjoy the artistry, why I can admire the fact that each of the game's rooms is a smart little spatial puzzle when you take into account lift placement, platforms, and robot behaviours, and why I can marvel over the fact that Caswell himself left game design behind to carve out a career as a poet, but the results don't frighten me the way they used to do.
I miss that: the thrill of exploring something fascinating but scary. Instead, I load Impossible Mission up and find myself dragged towards the tyranny of plausibility rather than the simple pleasures of the fantastic. I wonder, "How did I get in?" when I should be asking, "How will I get out again?"