Quite possibly the greatest shooter ever made... and also the most difficult game ever made.
There is a story, yes, but most people sadly won't care much about it. You play the role of a disgraced pilot named Shinra who is shot down near a remote village, inhabited by elderly people who had been exiled by an organization named Horai, which has been on a rampage of conquests for its own glorification. Shinra is dragged from the wreckage and nursed back to health and vows to defeat the Horai. To accomplish this goal the villagers entrust him with a fighter plane that they built themselves, called the Ikaruga. The Ikaruga is no ordinary fighter craft, however... It is the only ship of its kind that can switch "energy polarities" employed by your enemies and is launched via a massive transportation ship called the "Sword of Acala"
The graphics and sound are all surely top notch in this game but this "polarity" concept is what sets Ikaruga apart from most traditional shooters. The enemies you will encounter are either positives or negatives, that is, they fire either black or white energy. Your ship has the ability to alternate between the two. How this plays out is simple: If you are black, then the black enemies' bullets will be absorbed by your force field. However, white bullets will destroy you while you are black, and vice versa. The conventional methods of avoiding enemy fire is thrown out the window here as well since there is absolutely no way to avoid every shot fired at you; so many bullets fly from scads of enemies that the only way to get through a level is by careful switching of polarities to absorb most of your enemies' fire as opposed to avoiding it. After you spend a bit playing, and as the difficulty increases, it will literally be raining fire and brimstone in pretty much every available space on the screen and the strategy then becomes, not about dodging all bullets, but dodging the right bullets at the right time. Avoiding the right bullets is what will keep you alive because this game, while being short, is quite possibly the most difficult game this humble gamer has ever been humbled by. Hordes upon hordes of enemies fire a relentless onslaught of fire in your direction and the further you progress, the harder it is for you to keep up. Rest assured that you this game will test your finest reflexes, your best attempts at dexterity and your very sanity as you develop new colorful ways to profanely curse how incredibly difficult this game is.
To sum this game up, this is quite possibly the greatest shooter ever made. It's unmercifully difficult but the great graphics, great soundtrack, well-produced sound and challenging gameplay make this a requisite If you're a fan of shooters, modern or classic. Every gamer owes it to themselves to play this game and absorb every bit of it into their being.