The LG G5 is a curious creature, a commutable chimera that has two roles: as a standalone flagship smartphone, and as the nexus of a modular add-on ecosystem.

On its own, the G5 is a competent, playful device. But as the first phone to introduce modular components to the consumer market, it is a trailblazer.

Creating a modular phone has been somewhat of a Holy Grail for some smartphone makers over the last few years. A flexible, interchangeable set-up allows for easy upgrades, less electronic waste, greater customisability and lower overall costs.

Prominent examples include Google's modular smartphone Project Ara, which is scheduled to begin pilot testing this year, and indie projects such as PuzzlePhone and Phonebloks, which have generated significant traction.

But LG is the first major manufacturer to hit the market with two adds-ons: the LG Cam Plus and the LG Hi-Fi Plus with B&O Play.

Both attachments can be snapped on to the G5's removable battery, and then slotted back into the phone.

The Cam Plus acts as a handgrip, and adds physical shutter, video and zoom buttons to the camera, while the Hi-Fi Plus is a portable digital-to-analog converter for audiophiles.

For now, neither one is integral to the operation of the phone, and neither is there a guarantee that they will work with future LG phone models.

But they portend a future where phone modules can be swopped out like desktop components, and LG should be lauded for taking the risk of building them.

As a standalone phone, the G5 ticks all the right boxes, and there is a refreshing sense of playfulness pervading its design.

The 5.3-inch G5 sits easily in the hand, with its glass-and-metal alloy construction given a less severe edge by a layer of textured primer coating the phone's shell.

Its edges are pleasingly curved, although the bump on the back of the phone to house its dual cameras is rather prominent.

The G5's physical buttons are well placed and easily accessible, with a volume rocker and latch on the left, 3.5mm port on the top and a SIM/microSD card tray on the right.

Under the hood is the latest Qualcomm Snapdragon 820 processor, Adreno 530 graphics and up to 2TB of expandable storage.

In my time with the phone, it was unfailingly responsive.

In terms of performance, it is right up there with the best in the market right now.

The removable 2,800mAh battery of the phone is also a big plus, given that the ability to change the battery is something that is often missing from many high-end handsets these days.

To swop out the juice pack, press a latch on the bottom left of the phone to slide the battery and connector out. A tagline scrawled on the bright chartreuse battery makes the G5's design philosophy clear: "Life's good when you play more."

The phone's UX 5.0 interface is also cheerful, with bright and bold icons. The default UI does not have an app drawer, but users can get this convenient feature by downloading the LG Home 4.0 launcher.

The camera yields highly detailed photographs, and captures textures and small features well under both bright daylight and indoor fluorescent light.

It focuses fast, and I found the wide-angle mode a huge plus, as it was particularly useful when taking scenery shots or big-group photos in confined settings.

I did find the colours to be a little cool, though, and, in low light, the pictures were noisier than I expected. But most of the time, the G5's camera is more than enough to produce great pictures.

•The G5 is a playful, fun, high- performing flagship that heralds a possible modular smartphone future.