A.I.R Defense

A.I.R Defense is a meeting of two different species: a line-drawing game much in the style of Flight Control, and a rather loose take on tower defence.

When combining such distinct styles of gameplay, there's bound to be some discord, yet these seemingly distinct genres come together to form one solid idea.

From one level to the next, you draw lines to command a squadron of fighters in an effort to stave off wave after wave of enemy attack. The enemy takes many forms, from mundane tanks to the kind of bipedal megaton monster at home in a Metal Gear Solid game.

It's a simple idea made complex and engrossing with layers of depth and strategy.

The jets and helicopters themselves naturally cost money – money that's amassed by taking down enemies and picking up bonuses dropped via random air drops. You only have a limited number of spots in which to deploy fighters, so choosing the best craft for the task at hand is a constant challenge.

Some, for instance, are able to survey black spots for enemy tanks, while others spray mines that decorate the base's surroundings. There's also a series of power-ups that defend your camp, often serving as a last minute life-saver.

What's clever about each level is that the direction of all of the attacks appears random: should you fail, you won't be forced to retrace exactly the same steps, even though the army that faces you is identical in both force and number. It's a smart way of ensuring that repetition isn't an issue.

Up and down

Less clever is the sense of balance, or rather the lack of it. Stages swing wildly from cinch to cruelly difficult. It feels a harsh when you're on top of things one minute only to watch your planes crash to the ground the next.

While you can use credits to upgrade your arsenal, your forces can easily be shot down in a second, upgrades or not. This is no haphazard line-drawing romp: as the game progresses, you're increasingly required to track paths through what becomes a maze-like minefield.

Although this mix of highs and lows can lead to a certain amount of frustration (arguably the result of a lack of foresight by developer Colorbox rather than an intentional move), it soon becomes the accepted language of A.I.R Defense and, if nothing else, keeps you on your toes, just as war should.