Glance down the intricate family tree that connects the myriad successful Lego video games, and something striking is missing throughout the lineage. Most of those releases have only made cursory attempts at including that defining ability of the real-world toy: uninhibited construction. Aside from curio releases like the 1998 PC title Lego Creator, games based on the iconic bricks tend to allude to creativity, rather than offering freeform building in an unbridled form.

And yet Minecraft – with 120m sales and counting – has proved that there is huge potential in the idea of open-ended construction-focused games. Indeed, as Mojang’s creation evolved from a darling of the indie community to an international merchandising empire, it was comparisons with Lego that made the game easy to understand for players and, importantly, their parents.

The newly released Lego Worlds, then, marks a long-expected effort to reclaim some of the territory currently held by Minecraft. Perhaps wisely, however, it offers a spin on construction as distinct from that game as the broader genre allows.

In Lego Worlds, as various quests mould the player into a capable builder. Photograph: Warner Bros

For starters, you won’t have the ability to build your own landscapes for several hours of play. Lego Worlds is at it simplest a third-person adventure game built from digital bricks, and packed with quests, collectables and plenty to explore. Developed by UK studio TT Games – creator of properties like Lego Star Wars, Lego Lord of the Rings and Lego Batman – the fundamental structure will be familiar to anybody who has played a Lego game before.

The difference here is that throughout its campaign, this game gradually evolves towards being a creative experience, as various quests mould the player into a capable builder. And it is here that Lego Worlds gets a lot right. The framing of the narrative is much looser and more minimal than previous Lego titles. A spaceman has crashed-landed on the planet and wants to become a Master Builder. Equally, gameplay is much more open-ended. If there is an overall goal, it is simply to collect everything and play with everything. And after a few fleeting levels, new stages are randomly generated, rather than being meticulously designed. They remain full of objectives, tasks and hidden items, and are clearly not entirely random; for one, such stages can always be navigated and make sense as game spaces.

From its opening moments, then, Lego Worlds is a game that pays little mind to rigid structuring. It’s a perfect design choice for a development team clearly trying to toy with what player freedom can mean. In hopping from world to world earning and uncovering the gold bricks that serve as a currency for opening up the game and its character abilities, Lego Worlds introduces a number of tools that, on the whole, surmount the game’s most significant challenge: it must offer a workable creative toolset that can be harnessed using a game controller instead of the more practical keyboard and mouse.

There, TT Games starts out well. Tools are introduced one-by-one as means to solve puzzles. Quickly other abilities are introduced: copy and paste structures, raise and flatten land and scenery, and build brick-by-brick, along with a bounty of other options.

Capturing an item grants you the instant ability to place it in-game with remarkable freedom. Photograph: Warner Bros

The real learning for the player, though, is that Lego Worlds wants you to break its rules. With enough abilities and familiarity, it becomes apparent most challenges in the main story mode can be overcome through a multitude of approaches. Need to climb up a structure to find a stranded Lego figure? Flatten the building with a button press and you’ll meet your quarry at your feet, without ascending a pixel. Keep getting lost in a network of underground tunnels? Burrow through the walls and reshape the caves to your liking.

The most prominent means to interact with Lego Worlds is the Discover Tool. A 3D scanner shaped like a ray-gun, it can be used to capture hundreds of bricks, characters, buildings, vehicles and prefabricated scenery from each environment. Capturing an item grants you the instant ability to place it in-game with remarkable freedom. Sometimes that will deliver a means to solve puzzles, or simply an opportunity to replicate a steed to journey over a blocky landmass on. But really, the Discover Tool is establishing a library of assets from which you can spin your own environments.

Gradually, Lego Worlds relinquishes control, and over time freeform building and playing the game start to become one and the same. It’s a masterful way to guide players towards Lego’s vision of a creative experience. It’s just a shame there are a few too many flaws amid the foundation of that vision.

Firstly, there’s the rather curious decision to save opening a truly free building mode for when the player has earned 100 gold bricks – a tremendous undertaking that will surely inhibit the emergence of a content-sharing community. And while placing bricks and repainting landscapes with a gamepad is workable, away from the direct manipulation of digital Lego elements, Worlds feels unnecessarily complex and fiddly throughout. A mixed bag of unintuitive menus and other bewildering interfaces make navigating through the game sometimes painfully inefficient, and too often it’s simply not clear what to do.

Seemingly autonomous in-game cameras swing and sway eccentrically, frequently providing an obstacle to smooth interaction. And bugs currently persist, especially in terms of trapping characters in scenery; though at least the terraforming tools let you handle many of those problems yourself.

Add the sometimes perplexing control consistency, and Lego Worlds can really irritate, whether you are trying to place the camera so as to let you see vital on-screen text, or desperately plundering menu screens looking for a clue as to your current focus. And those randomly generated worlds – or Biomes, to use the game’s parlance – can be a little thinned out, especially as their size evolves through the story mode.

In spite of all that, Lego Worlds can be terrific fun, and its potential is vast. The effort in building the entire game from Lego bricks pushes anything TT Games has done before, and visually it is splendid, right down to capturing the various textures that real Lego bricks variously sport. It is also festooned with the character and detail that has made TT’s lego titles so popular.

The ambition is to be lauded, then, and much of the time, its realisation meets its creators’ aspirations. There is a sense that with just a couple of updates, Lego Worlds could leap from a captivating proposition to an essential purchase. But for now, the very loose framing that allows Lego Worlds and its players to be free from stifling game design conventions has equally made the experience sometimes ungainly and directionless, leaving its protagonists stranded in a world that is as full of confusion as it is ideas and potential.

Warner Bros; PC, PS4 (version tested), Xbox One, Switch; £25; Pegi rating: 7+