Metal Sun

The aliens are coming. In fact, they've been among us for some time. If they're not planning full blown invasions, they're abducting us in the middle of the night and shoving any number of probes into our bottoms.

Metal Sun doesn't indulge in such treats, but it does focus on another aggressive set of alien invaders. If you're expecting some kind of resolution either way, however, you might well be disappointed. There are no exploding White Houses here. Instead, this is pure arcade combat where holding out to post the highest score possible is the main aim.

Using the accelerometer to steer and a slider on the left side of the screen to control your speed, success is less about soaring through the skies and more about stalking your enemy from the word go. It's not a precise beast, the trick being to roughly line up your target in the centre of the screen before tapping away on the right side to fire shots.

Most of your time will be spent dogfighting. Strange ships that seem to hover in the skies are your main targets. Harder still are the metal suns and satellites that need to be taken down in order to level up. Though both seemingly wait around like sitting ducks, managing to direct your shots towards them is far from easy.

It's not about all out attack in this fight for planet Earth, though. It's also in your remit to protect humans on the ground, represented by blue orbs. These orbs are there for you to guard, but they can also aid you in your quest by boosting your health or adding to your firepower should you carry them onboard.

Not that any of this is clear if you jump right in. Aside from a fairly brief Help section located in the main menu, play begins without any instruction about objectives or controls, never mind any form of motivation or plot. Nobody likes lengthy tutorial modes or naff narratives tagged on, but having some kind of buffer to introduce play somewhat more leisurely would have been advisable.

As it is, Metal Sun lacks polish, assuming the feel of an amateur package. That's not necessarily anything to be sniffed at. Indeed, the occasional burst of visual realism would put some of the bigger publishers on the iPhone to shame. Unfortunately, it neither has the accuracy to truly depict a full-scale alien invasion nor the polish to pull off its arcade action with any sense of style.

It's ultimately a voyage that's too rough around the edges. Despite showing much promise, this is one that flight that's too choppy to handle.