Shadow Guardian is, without a doubt, the most ambitious title for iOS devices from Gameloft yet. Indeed, it's so content rich and full of graphical detail that it is surely stretching the boundaries of what is possible on the current generation of Apple products.

For starters, the game uses four-times as many polygons in its 3D renders than former Gameloft title Avatar, and utilises the retina display of the iPhone 4 to great effect, with greater drawing distances than ever before.

The game is in the Tomb Raider/Uncharted mould, giving you control over the wise-cracking adventurer Jason Call as he climbs, shoots and puzzles his way through a plotline that George Lucas and Steve Spielberg could have dreamed up. Or, failing that, certainly a bit of Romancing the Stone.

And just because Shadow Guardian is on a portable device, doesn't mean that it skimps on the single-player campaign length. It will take experienced gamers four hours to complete in total, and that's if you skip all the voice-acted cut scenes.

Action is split between the puzzle and platforming elements and good, old-fashioned shoot-em-up, although the latter is more of the duck and cover variety rather than go all guns blazing. There's also 12 separate animated executions that Call can perform on foes nearby, lending a spot of variety to the gameplay.

In Pocket-lint's experience so far, though, it is the climbing, jumping and mental challenges that most impress. Think PS2 Tomb Raider (when it was good) and you're halfway there. There are plenty of different environments to traverse, and some levels require a completely different way of thinking than others.

For example, on one level you have to find a whole sequence of mirrors scattered throughout, which have to be manipulated to allow a single beam of light to travel from one end to the other. A lot of thought has gone into it.

The other thing that we immediately noticed is how intuitive the control system feels. With no tactile pad, some 3D action games can be fiddly to play; not Shadow Guardian. It's cunning pace (not too fast, not too slow) allows for thought rather than mere button (screen) mashing.

Quite simply, from what we've seen so far, Shadow Guardian promises to be the most important game for iPhone and iPad yet. It could change the landscape of casual gaming forever.

It's also of our understanding that it will be released on both devices simultaneously and before Christmas. Look out for it on the App Store, where it'll cost the same amount as other Gameloft titles (around the £3.99 mark).