C.H.A.O.S.

It’s been almost five years since Apple graced the world with the iPhone, and in that time game designers have taken massive strides in iOS and Android development.

The first titles were basic affairs that tentatively explored how to best utilise the capacitive touchscreen, but more recent efforts have become incredibly complex.

C.H.A.O.S. - which stands for Conceptual Helicopter Assault Operational Simulator - shows just how far we’re come. It boasts a control interface that is so demanding it takes a while to become fully accustomed, but once you do you’re capable of some quite astonishing aerial acrobatics.

Getting to grips with C.H.A.O.S. isn’t easy. The controls require you to tilt the device and touch the screen simultaneously - it almost feels like the developer is expecting you to rub your belly, pat your head, say the alphabet backwards, and tap-dance all at the same time.

Moving your helicopter backwards and forwards requires a tilt in the appropriate direction - tilting to the side will force a turn. Your altitude is controlled by an on-screen pad, as is your strafing ability.

Weapons are similarly touchscreen-based, with machine guns, rockets, and lock-on missiles being available.

Your head is likely to spin as fast as your craft’s rotor blades when you initially pick up the phone, but the expertly designed training missions show you the ropes in a steady fashion.

By the time you reach the full-blown single-player assignments you'll be a little more adept behind the controls.

The eight solo missions include objectives such as defending an important location, taking out incoming enemies, and attacking hostile bases. You can tackle these at one of three difficulty levels, and they allow you to increase your experience level and earn cash.

After each mission, your performance is rated and you gain experience points, which allow you to progress through the military ranks. You use money to upgrade your helicopter or purchase a new, more powerful model.

All of this is merely preparation for the real meat of C.H.A.O.S. - the online multiplayer mode. You can face off against other players to achieve total air superiority, the thrill of dog-fighting with genuinely challenging opponents makes this a fantastically attractive proposition for competitive types.

Visually, C.H.A.O.S. is something of a stunner. The high-resolution 3D graphics are wonderful to behold, and the locations included within the game are packed with detail. We’d have liked to see a few more levels, but what's on offer is of a supremely high standard.

There’s so much to recommend about C.H.A.O.S. that it pains us to bring up its biggest failing - the reliance on in-app purchasing.

Even though this is a paid-for download, you’ll have to purchase additional cash if you want to advance as far as possible - some of the more advanced helicopters are only available for cash.

Earning enough money through pure merit will take ages, and you can bet that the online players with the most impressive numbers of kills will have resorted to buying their way to glory. Unless you’re prepared to do the same, the playing field is hopefully uneven.

Despite this blip, C.H.A.O.S. remains an entertaining aerial combat simulation, and one that shows just how advanced and engaging mobile games have become.