Developed by Google's "in-house startup" Niantic Labs, Ingress has been seen as the poster boy for Android gaming, offering a particularly Google-like take on the ad-supported, free-to-play model of games development.
Download Ingress and you'll be asked to choose a side: the controlling "Enlightened" or the anarchic "Resistance". These two factions fight over a mysterious new source of energy, with players using their mobile devices to claim ownership of prominent real-world landmarks, which attract this abstract resource.
In practice, I found when I played it on Android, you walk around your neighbourhood looking down at a map, over which pretty glowing green and blue lines flow. Find a source of power and you can claim it for your team, which usually involves overcoming defences placed by the other team, using various bombs and keys you collect.
The key is you have to be physically present at the place you're influencing, and it's this connection with the real world that has fuelled the game's popularity, with meetups of dozens and sometimes hundreds of players taking place in cities around the world.
"As Ingress is a massively multiplayer and location-based game, it makes sense for it to be available for as many devices as possible," said Jack Kent, principal analyst at IHS Technology. "Launching on iOS will greatly increase the number of devices and users for Ingress and thereby increase advertising revenues.
"This also fits with Google's wider mobile strategy," Kent added. "Google already offers almost 40 apps for iOS including Maps, YouTube, Chrome, Google Play Movies & TV. So this move is not out of character. Google's largely advertising based business model means it can offer its services on as many devices as possible regardless of operating system."
Ingress' ads are innovative, in that companies can pay to be featured in the game. Their stores become portals, which drives footfall. I often saw portals here in London that in the real world were pickup points for the car-rental service Zipcar, although I saw few other companies featured.
Niantic Labs is the brainchild of John Hanke, best known for creating the 3D visualisation software that became Google Earth. Niantic's purpose in the organisation is to explore the context of devices in the real world.
"I think [Ingress launching on iOS] underlines Google's drive to catch up with Apple in the gaming space," says industry expert Jasdeep Badyal of CCS Insight. "It showed this at Google I/O with its increased commitment and incentives for games developers. I still stink there's some way to go for Android gaming to match iOS but the efforts to get there are evident."
Google's Play Store saw 45 percent more downloads than Apple's App Store in the first quarter of 2014, according to figures from analyst App Annie. While the App Store generated 85 percent more revenue for developers, the Play Store generated 2.4 times as much as it did in the same period a year earlier.