The Lego brand, like Lego itself, is constantly being rebuilt in new and exciting shapes. What was once a box of building blocks has morphed into a series of video games, a TV and movie franchise, a theme park, and now a nifty AR app for smartphones and tablets. 

Lego Hidden Side is an app that works in conjunction with a range of physical Lego kits at a variety of sizes and price points. The one we were sent for this preview is called the Paranormal Intercept Bus, a large-ish 689-piece mid-range kit that took us a good couple of hours to put together. 

This isn’t a Lego kit review, but for what it’s worth the instructions were clear and the bus itself is nicely sturdy, with several moving parts. Along with the bus there’s a pull-out command centre that slots into the chassis, and a portable toilet that, like all portable toilets, turns into a monster under certain circumstances (in this case when viewed through the Hidden Side app).

The kit also comes with a handful of figures, and a few ghostly alternative pieces, such as a zomboid face that you can swap out for a normal one.

Who you gonna call?

Once you’ve built your chosen Lego kit and downloaded the Hidden Side app, the process is incredibly seamless. First, you choose whether to play as ghost or hunter in a fictionalised Lego place called Newbury. 

As a ghost, your aim is to hoover up green balls of gloom and fire it at various features of the map to haunt them, against a time limit, while dodging ghost hunter fire from above. You take a team into these rounds, with coloured portals letting you tag different team members in and out. 

But it’s the Hunter mode where the AR comes into play. Here your goal is to save Newbury by visiting various locations (corresponding to whichever Lego set(s) you own) and exorcising all of the ghosts from them and defeating bosses.

First, the app prompts you to scan your Lego set in, with a neon outline telling you where to point your phone. Once it clicks, your set comes to life on the screen, on a road, surrounded by buildings, trees, and other features. The bus even sets off down the road, giving the whole experience a nicely kinetic boost.

It’s an extremely robust use of AR. While the app recommends a well-lit room and a non-reflective surface, we found the tech pretty bulletproof. The app never failed to scan in our bus, and once scanned it was locked in, allowing is to zoom in and out by moving closer and farther away, swing around to take a look from different angles, and so on.

Your goal in Hunter sections is to clear gloom, kill spirits, and catch ghosts (perversely, these are the very ghosts you use for haunting in Ghost mode). The phone in your hand acts as a sort of paranormal scanner. Following prompts, you move the crosshair to the dish on your set to start hunting for gloom, and then follow the blips on your Aliens-style radar device to find the hidden splats of gloom. 

I ain’t afraid of no ghost

Each set comes with its own colour wheel, and you need to physically turn this to reveal and scan the colour of the ghost you want to hunt next. In the first instance this means clearing gloom, but when a ghost reveals itself you need to start firing. 

Shoot too frequently and your gun will overheat, while taking too much damage will run down your battery and end your turn. For a game ostensibly aimed at children, Lego Hidden Side isn’t particularly easy. You get to keep the gloom you bank, however, so it’s forgiving at least.

Outside the gameplay there are three currencies to accumulate and spend on various upgrades and so on. Subscribers let you collect various rewards, from gloom to energy to research slots. Gloom, meanwhile, lets you buy random upgrades, and spirit lets you upgrade your ghosts. 

As a casual AR game, Hidden World probably won’t give Pokemon Go any sleepless nights, not least because you can’t really play it without forking out for a Lego set – and you WILL be pestered to buy more once you buy one. 

But it offers a premium experience that Niantic’s juggernaut does not. Plus, the Ghost mode doesn’t require a camera, so it’s playable without AR if you happen to be away from your set and offline. 

As AR apps go, Lego Hidden Side is at the premium end of the market, with all that entails – robust tech, a polished gameplay experience, and a potentially high cost if you want to experience everything it has to offer.