It's pointedly reminiscent of Bizarre's score-whore shooter The Club, forcing you to replay stages, memorise enemy placements and study moves and manoeuvres to better your ranking. By your fourth or fifth play-through, Rage mutates from a rather listless shooting gallery into a tense choreography of perfect reloads, knowing dodges and pinpoint skill shots. It's a riot.
Or it would be if the controls were just that little bit tighter. Or, perhaps, if the game was on another platform. Because no matter how hard developers try, the first-person shooter will never find a truly comfortable fit on iPhone. In touch-screen mode, your fleshy thumbs obscure the view and you're far too slow to successfully swing between targets and enemies. In tilt mode, you have to recalibrate the game every time you change seating positions. It's hardly the pick-up-and-play intuition of Angry Birds.
It's not that the genre is an impossible fit for the device – Gameloft has seen plenty of success with its Halo clone, NOVA – but the frustration is thoroughly exasperated by Rage's on-rails nature. Trying to reload, change weapons or dodge by slapping against random bits of glass is a pain when you're frozen to the spot and surrounded by killer chumps. And shooting a tiny bulls-eye target as the camera vigorously whips around the next corner sucks.
Plus, with only three levels, three guns and three types of enemies, Rage is lacking in content. Believe it or not, there's no huge difference between some rotting tenements, a grimy asylum and a putrid underground bunker. There are (currently) no leaderboards or achievements, and the options menu feels distinctly sparse, with no way to move the virtual buttons about or listen to your own music collection in-game.
It all comes off feeling reserved, rushed and slightly unfinished, tipping that balance away from legitimate game and towards tech demo or promotional toy. Sure, it looks incredible, from the lush, downtrodden environments to the creepy, feral animations of the mutants. It's probably worth the couple of quid just to show off how powerful your device is.
Had Rage been properly fleshed out, it might have really been something. Coming from John Carmack, it almost feels like Doom: Championship Edition – a tired old game that's been sped up and retrofitted with a tasty layer of meta-game, while instead of Pac-Man's dizzying rave theme, Rage goes for cheering crowds and bellowing commentary. It could have been a proud salute to the genre Carmack christened.
But it's not. It's a fun distraction on your mobile, giving you a few hours of entertainment to rack up a high score, finish all the stages, and gawp at the tremendous graphics. Like I said, worth a bob or two.
6 / 10
Rage is out now on iPhone, iPod Touch and iPad. It's 59p for older devices, and £1.19 for Rage HD if you want the high-resolution graphics on iPhone 4, the fourth generation iPod Touch and iPad.