Parallel Kingdom publisher PerBlue has revealed the title now has more than 100,000 players on board.

The massive multiplayer trans-reality game launched in 2008, and is free to download on iPhone and Android, uses the phones' GPS to merge a virtual world with real life locations.

Players are encouraged to explore their local environment to enable them to encounter monsters, and discover treasure hidden in the city streets.

It's yet another genre offshoot that's found its feet on mobiles, with the gameplay directly tapping into the technology available within modern handsets.

Similar, albeit using a different theme, is iPhone Mafia game Turf Wars.

World to win

The publisher made the announcement on its blog along with a whole load of other stats - players founding 1,015 different cities worldwide, claiming 425,000 km² of territory across the globe.

Clearly keen to expand its userbase, PerBlue actually believes that's not such an impressive stat.

"That may sound like a lot, but it's less than 1 percent of the Earth's surface," the publisher states. "That leaves 509,647,000 km² of spacious unclaimed territory - go claim some."

You can find out more information via PerBlue's blog and the game's website.