In a 2005 interview with Eurogamer, Director Shinta Nojiri said Kojima asked his team to take a ‘different approach’ when developing a game to complement 2004’s Metal Gear Solid 3: Snake Eater. That direction led to Metal Gear Acid – a grid-based, turn-based, decking-building PSP game whose villains are a pair of sentient, people-murdering, plane-jacking puppets.

It doesn’t sound like Hideo Kojima’s sneaky, sneaky, peaky, peaky PlayStation classic – except for the convoluted description and the sentient puppets bit. Yet the two share far more DNA than you’d expect: Acid has all the beeps and the boops and the cardboard boxes and stuff and things we look for in a sneaking special from Kojima Labs Inc.

And yet it’s one of the greatest genre shifts you’ve never played — a game that sits on the periphery of our collective video game consciousness as that Metal Gear card game on Sony’s first handheld.

Consider these words, then, an attempt to elevate Acid’s place in that consciousness. It’s a look at what Acid is, and what its legacy might be.

Metal Gear!?

Acid’s gameplay just works. Enter a grid-based arena with a deck of cards that you can either burn to move, play to perform an action, or outright discard. Actions range from firing the iconic SOCOM pistol or donning the classic cardboard box, to setting a spicy mine or consuming a ration to heal up.

It sounds simple, but Acid piles on unexpected levels of complexity: status effects, resistances, directional damage bonuses, mid-mission objective changes – just some of the things you need to consider when building your deck. Buy cards with points earned from completing missions, or pick-up game-themed packs mid-mission. Dozens of decisions you need to make before ever leaving Acid’s menu.

And when you leave that menu, you can’t condemn yourself to Game Over by misclick or miscalculation because your deck always resets. You’re inclined to burn irrelevant cards on movement and discard down to the perfect hand, then execute.

But that often leaves you waiting to pull the perfect piece of digital cardboard without tension or consequence. The lure to procrastinate for the near-perfect play is a powerful one, and Acid’s pacing often pays the price. Enemies go about their daily routines blissfully unaware of your hand-building antics in some remote corner of the map. Rarely is there pressure to make do with what’s in hand.

Solid in more ways than one

Nojiri and co. emulate components of the Metal Gear experience: patrolling guards, sweeping cameras, alert statuses, giant exclamation marks, big-silhouette bosses – those Metal Gear staples are cloned here in fine portable form. There’s even the mandatory return trip to previous missions to retrieve items for subsequent missions. Annoying, perhaps, but so, so Metal Gear.

It’s not a card game inspired by Metal Gear – it’s a Metal Gear card game.

But details around how this card game was made is about as rare as a short Kojima cinematic. That arguably gives us license to summarise what went on: Nojiri understood that Metal Gear Solid is effectively a turn-based game, and saw fit to transplant that essence into something far more literal for portable play.

But Solid isn’t turn based, you cry. Yes, I retort, Metal Gear Solid is turn-based. Or, more precisely, it’s about waiting your turn. You watch, they walk, you watch, you move, or shoot, or strangle. Both Solid and Acid demand you think before you act. They demand that you think before taking your turn.

It’s why Acid feels so familiar – so Metal Gear – despite its ‘different approach’. Like Solid, sometimes the best thing to do is do absolutely nothing at all. Like Solid, the best plan of attack is often not to. And, like Solid, you can do Solidy things like knocking to lure guards off their beaten path, or shooting those damned cameras in their damned camera faces.

And those Metal-Gearisms are a constant source of surprise here. Each new card reveals a new tactical option, and another -ism you can’t help but smile at. In typical Kojima form, Acid’s cards become self-referential. Metal Gear Solid 2’s Olga Gurlukovich draws three additional cards into your hand, bringing with it a snippet of a scene from the PlayStation 2 game itself. Silly, but not off brand.

Acid, then, feels like a window into an alternate reality where mainline Metal Gear was actually a turn-based card battler. One where, if you had amnesia after some tragic accident, you wouldn’t question that this was the Metal Gear Solid — so convincingly does it capture the feel and themes of the series proper.

Each failure is a reminder that Acid is indeed a strategy game, bringing with it all the rewards and reprimands the genre courts. That means it can just feel difficult. Little does it help that past Solid games have conditioned us to their immediacy, where escape is mere seconds away. In Acid, that escape could take a dozen turns and just as many minutes. You can’t just fix things here, as you’re forced to play out the consequences of your failures in an incremental, turn-based fashion.

But there’s an exhilaration to that difficulty, to hoping you get that essential crowd-control draw as the music kicks in and you’re swarmed by six heavily armed goons who, as it happens, fight just like you. They have decks, they have equipment, they have those special abilities. They’re players on the board who feel as deadly and capable as you do. It’s something you absolutely feel when things go wrong, something that even a procrastination-laden hand can’t always account for.

You could say it’s Metal Gear Solid, and Metal Gear, but solid.

There might be a reason for that difficulty, though. In a video interview – the second piece of promotional media I found for Acid – Nojiri says the game was rushed to meet the deadline of the PSP’s Japanese launch in December 2004. It’s perhaps why Acid starts to fray at the edges, where it includes things so obviously annoying that anyone would’ve fixed it – had they time.

But they didn’t, and that came with a cost.

Also not so solid

You could describe Acid’s visuals as PlayStation 1.75. Not quite the polish or frames of its PlayStation 2 cousin, Sons of Liberty. Not quite the jagged blockiness of the series’ 1997 fifth-generation debut. It feels suitably next-generation for a console informally branded as ‘PlayStation 2 in your hands’. It looks suitably Metal Gear and it sounds suitably Metal Gear – except when it doesn’t.

Because there’s no voice acting.

It’s a decision that feels very un-Metal Gear, and decidedly at odds with the series’ cinematic aspirations. Especially so, given that 2010’s Peace Walker went on to prove that developers can make Sony’s debut handheld speak. Gone is the classic black codec screen, gone are those overwrought vocal performances — replaced by on-screen text you have to fight through to reach the card-drawing carnage.

A Solid cinematic meant setting aside the controller and indulging in both the beautiful and the absurd, each a feature presentation unto themselves. Here, there’s an anticipatory dread knowing something not gameplay is on the way. It feels unbecoming of a device touted as a movie-playing machine to embrace a presentation that would totally be at home on Game Boy — not unlike 1997’s Metal Gear spin-off Ghost Babel.

There’s that difficulty, too. In the same Eurogamer interview, Nojiri copped to the game’s tutorial not being up to scratch. It’s not quite a fatal flaw, but it might be fatal for some. Those Metal Gear tropes bring with them a set of expectations, meaning it’s easy to think you know Acid because, well, it’s just Metal Gear Solid with cards. But it’s not quite that, and can leave you exasperated when it defies the foundations set by Kojima prior.

And that tutorial doesn’t make those differences quite clear, often relegating key details to pop-up messages in between missions. Not a game killer, but not the smoothest landing for a game that’s attempting to transform a beloved property, and navigate the scepticism that inevitably follows.

And what follows is Acid’s legacy. If it even exists at all.

Acid’s lasting legacy

That transition to turned-based card battler makes Acid an accidental time capsule from 2004. It decisively steals control from the player, moulding real-time movement into guided, grid-based combat with randomness – a categorical inversion of it modern-day peers who scramble to be anything but turned-based, even at the risk of compromising their long-standing identities.

Acid is a potent reminder that turn-based wasn’t always a dirty word.

But for a series whose core themes include legacy – what we leave behind – Acid feels like a game without one. It wasn’t the first 3D Metal Gear on a non-Sony console, as that honour went to 2002’s Twin Snakes on GameCube. It wasn’t its first handheld outing either, as that went to the aforementioned Ghost Babel on Game Boy. That, coincidentally, was also directed by Shinta Nojiri.

Perhaps its legacy is to be known for taking a risk, to be known for expanding Metal Gear in a way that’s engaging, strange, unexpected, and portable without corroding the essence of its inspiration. Perhaps its legacy is to be an example of how to successfully transform an action game into something distinctly not action.

Yet even this legacy is failing us. Many Metacritic links for Acid are dead, or point to the wrong game. Inked reviews are now long past their print run, forever forgotten. From what is available, IGN said Acid will ‘burn a hole in your patience’, whereas PSX Extreme said that it’s ‘easily one of the best turn-based strategy games to come along in years’. Both feel true, and both perspectives feel like an average of its solid-but-not-spectacular Metascore of 75.

And that could explain why there’s something bittersweet about that Eurogamer interview, as short as it is, as old as it is. A sense Nojiri ran out of time to make a good idea great. He knows what he’d change – like a student handing a draft to their teacher and trying to explain what that last paragraph was meant to be. Proud of what he’s done in spite of the circumstances surrounding its development, and proud of what he thinks it can become.

And it’s for precisely this reason you should play Metal Gear Acid – because it represents a risk taken with a multi-million dollar property the likes of which we seldom see today. A game whose director and his team played a winning hand despite the deck being stacked against them, who found success enough to make the improvements he wanted, to finish that last paragraph, in a sequel released just 357 days later.