We've been waiting for augmented reality gaming to take off for about as long as we've been waiting for virtual reality and smart watches to become viable.
And while the latter two might finally be taking shape, AG is still some way behind.
Of all the attempts to blend the boring real-world with a splendid smartphone game, Ingress has achieved the smoothest and most effective set of mechanics we've seen so far.
It's still very much a niche within a niche, and only a hardcore fan base is likely to support it, but those fans will have a fantastic time running around in its blurred sci-fi reality.
Playing with portals
There are two factions at play in Ingress. You can choose whether to join the Enlightened, who believe the inter-dimensional influence of 'The Shapers' is intended to help mankind, or the Resistance, which seeks to protect humanity from this otherworldly interference.
Around the world - the real world, that is - portals are opening at prominent landmarks. Statues, sculptures, and anything else that stands out could be a potential portal target.
These portals emanate 'exotic energy', which is all you'll see of the mysterious Shapers. Your task is to visit the landmarks and claim or capture the portals for your chosen faction.
If you're the first one to find a portal it's easier to claim than if you're trying to take it off the opposing side, or 'hack' it. Up to eight resonators, which collect up the exotic energy escaping from the portals, can be positioned around to syphon off the power for you and protect it from the opposition.
Naturally this means equipping yourself with these essential resonators. You can make them by modifying your existing items, or pick them up in the outside world.
A wide variety of virtual technology is dotted around the map after being dropped by other players.Keepin' in real
Ingress's UI is a modified Google Maps with a deliciously atmospheric sci-fi overlay. You use this to locate nearby portals, and since the game has been running for a while on Android there's a decent number even in less populated areas.
Our local park boasts a portal or two, and minor monuments we walk past every other day without paying attention to have suddenly been designated as Ingress points of interest.
It's a complex game, though. You're not just securing portals, but attempting to link them together to gain points through triangulated positions on the world map.
There are weapons at work and hacking requirements, and if you don't level up your tools your efforts are easily overturned.
Anomalous bursts of exotic energy break out and cause factions to become a lot more aggressive in certain areas, so Ingress can leave your head spinning through sheer volume of notifications alone.
The game doesn't ask for any real-world money, but it does demand deep real-world participation. It's quite an undertaking, both for the developers and for you.
This is a game that rewards physical interaction and teamwork, so you really have to ask whether you're willing to give it that kind of commitment. Especially when it means regularly revisiting portals or heading further afield to capture or convert new ones.
No small amount of travel is necessary if you really want to immerse yourself in its thoroughly decent sci-fi mystery, and you'll need friends both new and old to climb its ranks.
But it gives back in abundance if you do decide to dedicate yourself to this bold new premise.