The SpongeBob Movie: Sponge out of Water happens to be the very first encounter the present reviewer has ever had with any aspect of the SpongeBob SquarePants universe outside of its dementedly peppy theme song. I lead this fact in the spirit of full disclosure, and also as a warning to the reader: I have no idea when I'm talking about. When I go on to talk about how it was pretty damn good all in all, as I am about to do, I'm comparing it to nothing at all. It could be unambiguously worse than anything that has previously involved the dimwitted, boundlessly optimistic talking, clothed sponge and his friends.

But even so, it's pretty damn good, all in all.

The film comes on the back of an early contender for Most Misleading Ad Campaign of 2015: it is not at all a Smurfs-esque adventure in which animated characters are turned into fully-rendered CGI figures wandering around in the live-action world. This aspect of the film is held until rather close to the end, making up - tops - 20% of the total running time. Instead, is a far more precious and rare kind of thing: it is a theatrically-released 2-D animated movie produced by the American film industry. Though really, as exciting as that is, it's still selling things short: Sponge out of Water is a mixed-media project combining at least three entirely different types of 2-D animation alongside its scenes of 3-D cartoons interacting with flesh and blood people in scenes shot by the live-action unit to be eye-searingly bright, with glowing, oversaturated colors that help the very stylised designs of the animated characters fit in better.

Visually, then, it's a film of rare ambition in family filmmaking, the obvious result of passion and care. It's a film made by people whose first priority was to realise their idiosyncratic ideas without compromise, and only second to continue feeding the maw of a franchise that was born almost sixteen years ago with the SpongeBob SquarePants TV series. Which is, I have to admit, really heartwarming.

So do is it with the writing, which veers madly from purest inspiration to deeply lamentable crap jokes and back again without pause, but never deviates from one peculiar mission: to provide, in a format that very little children can enjoy, a level of genre-blending non sequitur-based storytelling that borders on open surrealism at times. Whatever else we can say about it, Sponge out of Water is a profoundly weird movie: it opens with a flawlessly stereotypical pirate, Burger Beard (Antonio Banderas, holding nothing back) plowing through the Caribbean with a flotilla of adorable talking seagulls for his ...crew? Pets? It doesn't matter, anyway. Quite without explanation, he's doing this in what appears to be the modern world, where he plans to turn his pirate ship into a food truck. That kind of unapologetic "this makes no sense whatsoever, and you're just going to have to live with it" mentality is typical of children's television and avant-garde experimental narrativity alike, and if I didn't already know, I'd be hard-pressed to say which of those two trends Sponge out of Water would rather fit into.

The main plot of the film, taking place in the wholly 2-D underwater community of Bikini Bottom, finds the secret recipe for the cultishly adored Krabby Patties going missing, thrusting the town into a hellish post-apocalyptic nightmare world, from which it can only be saved by the combined efforts of boundlessly upbeat - even manic - SpongeBob (Tom Kenny) and the obnoxious, scheming, selfish Plankton (Mr. Lawrence), who build a time machine in order to prevent the recipe from ever being lost. And things get more complicated from there. The hop-scotching plot development - which I presume to be an inheritance from the series and its short episodic format - does two wonderful things for the film: one is that it prevents it from ever slowing down and becoming predictable, the other is that it acquires the babbling stream-of-consciousness of energised kids at play. The film is absolutely deranged, in the best possible way, and the fluid mix of visual styles matches perfectly with its anything-goes writing.

Eventually, this does all become wearying - the movie never shakes the sense that its natural home is on television, where one can drift away from it for a few minutes here and there, or at least divert one's attention. It's certainly not like any of the visuals are clearly suited to a big-screen presentation. As it is, there comes a point where things invisibly turn into an endurance test to see how long we can withstand the non-stop assault of humor, which comes in the form of absurd wordplay, scatology, parodies of things the target audience can hardly have been supposed to have heard of, and just plain randomness. Despite the obviously sweet-natured optimism driving all of this, with its genuine affection for its characters and desire for all them to end up happy, the film doesn't rest for a moment, turning even its handful of "can't we ventriloquise the theme for a scene?" layovers serving mostly as an opportunity to introduce new sorts of jokes, new visual styles.

For me, I started lagging behind right about when the characters popped out into live-action; I imagine other viewers will run out of steam earlier or later, maybe all the way at the end. But it's a lot of stimulation packed into 92 minutes, more than I can pretend to have been ready for. The film is delightful, and inventive, and wonderfully enjoyable to look at; but the film is also busy, and the lack of even a single built-in breathing break made it hard for this particular grown-up to get the full effect of all the kid-focused zaniness.