Our fascination with mass destruction, as morbid as it may be, is the source of so much entertainment these days. That some inexplicable force of nature would doom humanity is such an intriguing premise that we can't help but gawk in amazement. Asterope embodies both things - extraterrestrial terror and simplicity. Here is a game that entertains as much as it innovates and yet remains simple enough for the ride to remain totally enjoyable.

When an asteroid on a path of destruction towards Earth sucks up a space shuttle filled with astronauts sent to investigate it, you're the only person on the planet willing to brave a rescue mission. Hopping into a miniature spaceship, you take to orbit and launch an effort to find out what happened by venturing inside the asteroid.

Your vessel is unusual in that you don't have direct control over it. Instead, you manoeuvre about the asteroid's innards by means of a grappling hook. By tapping the screen, you make your ship fire a rope with a grapple hook that latches onto the rocky sides. Latching onto an outcrop above your ship, for instance, allows you to turn in that direction. The longer you remain hitched with the hook, the greater the turning angle. A red button located at the bottom of the screen lets you detach at any time.

Asterope is all about timing. You carefully survey the surroundings and then time firing off the hook to make successful turns. It's a very deliberate game - far from reaction-based. Movement must be plotted out in advance, otherwise you set yourself on a crash course by reacting to obstacles rather than planning your moves ahead of time. In this way, the game forces you to take a innovative approach to navigation.

Given that you're sent to rescue fellow astronauts from the asteroid, many of the main quest's missions have you moving in close to pick up stranded spacemen. These astronauts have stationed themselves along the rocky surface of the asteroid, meaning you have to steer close to the edge in order to pick them up. This requires an inordinate amount of precision, which makes Asterope simultaneously challenging and frustrating.

For each level you're only given so many lives; lose these and you have to start from the beginning of that mission. Obviously, this becomes an enormous source of frustration when you reach the final stages of a level only to lose your lives trying to rescue that last astronaut and have to start the whole level over again. Of course, it also makes the game immensely challenging.

Completing the 10-mission main quest shouldn't take long, at which point you can try out the additional three arcade modes unlocked by completing the campaign. They're a means of extending the value of the game by presenting you with new objectives such as racing through the asteroid picking up stars for points.

As welcome as these extras are, much of the game's charm remains with the main quest. Asterope wrangles a recommendation not solely on its invention, but due to the way in which it combines it with colourful graphics and humour. It's charming - the sort of game that makes you feel good when you play. Considering it's only $3.99/£2.39, you can feel pretty good about plunking down the cash for it too.