Right now, there's a lot of experimentation going on among App Store developers.
With titles like Blackbar, game makers are playing with our understanding of what it is that constitutes a game.
With Zombies, Run, meanwhile, Six to Start takes the shape of a game and wraps it around our lives.
Codename Cygnus is an experiment, too, albeit one that's not quite so successful.
To all intents, it's an audio Choose Your Own Adventure set in a James Bond-style universe of espionage, counter-espionage, and man-eating sharks.
Shaken, not stirred
You play a suave secret agent out to thwart a terrorist known only as Neptune. There are bombs, there are hostages, and there's a secret organisation called Trident that's holding the world to ransom because it likes fish.
The adventure plays out as a series of audio snippets. Various characters - including your handler, your boss, a Miss Moneypenny clone, a rogue agent, and a femme fatale - talk you through what's happening, then offer you a choice of actions.
Do you punch the guard in the face, or hide behind a pillar and wait for him to go past? That sort of thing. Each choice is given a single word descriptor - you can be charismatic and charm a character, or you can be athletic and take it for a dance.
When it's time to choose, you speak the word into your iPhone. If you'd rather, you can tap on the screen to select an option.
The story is broken up into different chapters, each of which ends on a cliffhanger of some kind. They're entertaining in a simple sort of way, but there's a lack of polish and direction sometimes that left me feeling a little flat.
Yes or no?
The game is lacking in the interactivity department, too. It'd be nice to have more control over your actions, or have your choices less well signposted. Instead, you have two choices and they're spelt out for you precisely.
Codename Cygnus is definitely an interesting experiment, and it'll be intriguing to see how the story and the technology develops.
Right now, however, the adventure isn't quite thrilling enough and the choices aren't quite free enough to wholeheartedly recommend it.