With the incredible lore and stories of 70 or so episodes, and the infectious glee of the adored series, it’s hard to see how you could go wrong with an Adventure Time RPG. Well, if you would like to find out, read on. Here’s wot I think of the abysmal Adventure Time: Explore The Dungeon Because I DON’T KNOW.

Oh my goodness, I persisted. No one can say I didn’t. I stuck with Adventure Time: Explore The Dungeon Because I DON’T KNOW (ATE) for 27 levels. That may not sound like much. It took, maybe, four hours, and then crashed losing me an hour’s tedious, miserable progress. And I can’t bear to carry on. I’m so astronomically bored I’m a danger to satellites.

I really enjoy Adventure Time. I think the cartoon is wonderful, in its splendidly disjointed and freeform way. I love the characters, the voices, the locations. It has so very much going for it. So it leaves the rather stark question: why developers WayForward decided to dump all of that, and set it in blandly repeating featureless dungeons, interspersed with a tiny handful of endlessly repeated barks, with no joy or imagination whatsoever?

ATE is a phenomenally boring game. That’s a word we don’t usually use in reviews. “Only boring people get bored” I hear echoing in my head. But this offensively dull affair takes the repetitive nature of the typical dungeon crawler, and distils it down to its most banal, wearying essence, and titrates it directly onto your screen. Where that perpetual clicking usually creates a sort of hypnotic pleasure, incessantly dazzling you with new loot, new improvements, incremental change, here all that is taken away, and it’s just the unrewarding button tapping, slowed down to a slumbering crawl.

So, Princess Bubblegum has been keeping lots of prisoners in her 100 floor dungeon, but they’ve been escaping. You’re tasked with battling your way down and down, hitting them all until you find the end of your own personal tether. You can play as Jake, Finn, Marceline, Cinnamon Bun or Peppermint Butler, with other characters unlocked as you go. Other characters you “rescue” become quest-givers, with the apparent plan that you’ll have a bunch of tasks and an ever-expanding dungeon to explore.

Except what you get is ten near-identical levels between bland, or poorly conceived boss fights (of the two I could stand to stick through), in which you trudge around hitting or throwing things at the piddling number of enemy types, gathering treasures to buy upgrades back on the surface. It’s best played with a gamepad, since it was overtly designed with one in mind, and involves walking toward the identikit enemies and pressing B. There are other options, but you don’t need them. There’s no variety, no surprises, no sense of exploration or achievement. Just ten bland levels of the same thing, before the tile art changes and you do it all over again.

Dungeons are the same shape each time, with no challenge to exploring them. The minimap is god-awful beyond belief, and utterly belies how little effort went into crafting the places you spend 99% of the game – just grey rectangles either dark grey or light grey if you’ve been in that section. No detail, no care, no suggestion that there’s any more to this than the single-minded chore.

Every five levels you can come back to the surface and spend your treasures. Either on items, or upgrades to each character. However, an upgrade to Finn won’t upgrade Jake, etc, meaning that to get any of them up to a level to survive later dungeons, you’d have to replay the earlier ones – oh God, no, please, no, [wakes up sweating].

Anything you don’t spend is sacrificed when you go back down, so there’s no saving up for anything decent. So instead to get anywhere it’s a case of picking a character and persisting. After taking Jake and Finn down, I became thoroughly sick of hearing the same one or two word barks for the 900th time (perhaps with the exception of Jake’s saying “SCOOP!” every third time he picked something up, which for some reason worked for me.) I in the end opted for Marceline, who thanks to her vampiric hovering ways can at least float over the tedious array of pits that litter every floor. Her gentle voice keeps me slightly more calm, even if she only says about three things.

All these voices are provided by the proper cast, and it’s just so sad that it’s all wasted in such a dreadful game. So you’ve got Jeremy Shada (and his now far too old voice, poor thing), John DiMaggio, the incredible Tom Kenny, creator Pendleton Ward (although seemingly having forgotten how to do Lumpy Space Princess’s voice, devastatingly) and the rest of the regulars, alongside fantastic guest stars of the likes of Andy Milonakis, Neil Patrick Harris, Maria Bamford and only bloody Stephen Root.

Yet, as you play the game, by its very nature they never interact. So from its opening concept, the game never had a chance of capturing what the show is all about. In the scripted sequences above ground there are flashes of it, but it’s all so stilted that there’s no flow, no punch.

This is all then rendered even more clumsy and peculiar by the weird decision to half-make it a tribute to classic Nintendo RPGs. Not the way the game plays, at all, whatsoever, not one bit. But the cutscenes, which are static letterboxed images of the characters rendered in crude pixel form, with white Nintendo-style text below, and the dungeons and characters themselves, which are meaninglessly “retro”. Why, when your source is the gorgeously loopy and bendy animation style of the Cartoon Network success, would you instead deliver extremely poorly animated sprites?

It’s such a weird decision, made even more so by the frequent cutaways to the characters drawn properly. Use Finn’s “special move” (it’s so, so not special) and you’ll see a gorgeous drawing of Lady Rainicorn screaming something in Korean just as she should be, before it cuts back to the grainy, dreary faux-pixel bore of the main game. Just knowing they could have delivered something that at least looked like Adventure Time is made more gutting by how completely irrelevant the retro styling is. If the game played like bloody Zelda, then fine! But when it’s like a half-arsed 69p iOS game released at a premium price on PC and current gen consoles, it’s madness.

As I played, I tried to work out who it was for. Adventure Time, the TV series, occupies that wonderful space of being completely engrossing to children, while equally so for adults. I think perhaps there was an attempt to do the same here, creating a game that maybe parents could play with kids? I’m not entirely sure, but their opinion of children can’t be that high if they thought something this vacuous and bland would be good enough to entertain them. I sentence everyone involved to playing TT Games’ Lego series until they finally get it.

This is a game with the entire creative team of the show, the array of extraordinary voice actors, and the freedom to explore that world, and it’s set in agonisingly monotonous rectangular dungeons, with characters who don’t speak but for shouting the same half-sentences until your ears crawl off your head and hide under your armpits. If it were a cheapo mobile game getting a Steam release, you might not mind wasting a couple of quid on listening to the character chatter up top, before quickly tiring of it. But £30?! What were they thinking?

In the end you’ve got a game that doesn’t look like the cartoon it’s based on, certainly doesn’t even try to capture the atmosphere of its source material, completely misunderstands how dungeon crawlers work, has the most dreadful, tinny chiptune music, and looks apathetic in every element.

This could have been a wonderful RPG, set in the show’s array of utterly fantastic locations, quests and side-quests sending you on various journeys, with pretty much the same combat mechanic. It could have been something that celebrated Adventure Time, made use of the amazing resources it had to hand. But instead this is an insipid, limp waste of it all, and a proper shame.

Adventure Time: ETDBIDK is available on Steam for the astonishingly stupid price of £30.