Ikaruga is a vertically-scrolling shoot-em-up for the Sega Dreamcast and the Nintendo GameCube. Created by Treasure, it is the spiritual successor to their earlier game Radiant Silvergun for the Sega Saturn, which is why the opening screens of Ikaruga give its codename as "Project RS2", though the games are related in genre only.
Gameplay
Ikaruga ("IH-kaa-ROO-gaa")'s gameplay revolves around the very basic concept of polarity. Every enemy in the game, and every projectile they fire, is one of two colours: black (tinged with red) and white (tinged with blue).
Your ship, the titular Ikaruga ("Spotted Dove"; all the ships in the game are named after birds) can switch between these colours at will. Also, it has a shield-type thing which will absorb projectiles of the same colour. If a sheet of white lasers are aiming right at you, switch to white and you will breeze through them. Meanwhile, a single contact with a single projectile of the wrong colour will destroy your ship instantly. So, while, for some of the game, it is practical to simply move around and dodge everything on the screen, it is, more often than not, impossible to avoid being hit by some kind of attack, so you have to switch colour rapidly and skillfully to stay alive.
You can defend yourself, of course, by returning rapid fire of the same colour your ship currently has. If you're black, you fire black lasers, white, white. Shooting enemies with the opposite colour is more damaging than shooting with the same colour, though you still do some damage either way. Your gun has infinite ammo but cannot be upgraded in any way.
Already, then, we have some potential tactical conundrums.
A black enemy is coming towards you, spewing black laser fire.
Do you switch to black, to safely absorb the laser fire? Or do you switch to white, the better to kill it faster?
A wave of black dots is sweeping towards you from one direction while a wave of white dots is sweeping towards you from the other direction.
You can't pass through both of them at once, so what do you do?
The boss keeps switching colour.
Do you stick with a single colour of fire, the better to maintain your concentration as you dodge its attacks? Or do you switch colours in synch with it, to wear it down more swiftly before you die?
These are among the most straightforward challenges. The situation becomes much more complicated once you factor in:
Difficulty
Ikaruga is a relatively brief game, consisting of five individual levels, each closing with a boss. The whole game takes about 25 minutes to play all the way through.
Once you get good enough to get that far.
As previously stated, a single shot of the wrong colour will kill you in this game. Combined with a relatively small stock of extra lives and an even smaller stock of continues once all your lives are lost, the average gamer is extremely lucky to live to see the first boss on his first attempt.
The amount of time you spend playing is logged, and as you play for longer, you are granted the option of more continues until eventually you are given infinitely many - enough to get right through to the end. So, eventually, you will get to see the whole thing.
Even if you die horribly once every five or six seconds, which you will.
Consider the opening moments of level 2...
The game mechanics are entirely two-dimensional but the ships and backgrounds are rendered in wonderful 3D, so you're swooping over a lovingly rendered mechanised city at high speed. Tiny fighter jets begin spiralling in from the top left. Fine. Then they come in from the right. And the bottom left and bottom right. At the same time. They spiral in to the centre of the screen and if you still haven't shot them by that point, or collided with them - oh, did I mention that a physical collision with anything solid is fatal in this game? Because it is! - they home in on you. And this entire time, each one of them is shooting at you, small, slow-moving black and white blobs, which you have no choice but to dodge or absorb at the same time.
Anyway, that's one of the easiest parts of the game.
How about the boss of level 3?
There's a wide ring of sixteen turrets, alternating black and white, with you trapped in the middle. The ring is constantly rotating and the turrets are all firing inwards. Your job is to switch colours rapidly to absorb the fire of the nearest turret (thus staying alive) while wearing down and destroying each turret, ideally using opposing colours for speed. Easy enough, yes? Just hold down the fire button and concentrate on staying the right colour...
Okay, well, each time you destroy a turret, the ring spins a little bit faster. Also, the ring has a hub, which you also can't collide with. The hub has two heavy lasers mounted on it. The lasers alternate colour while firing outwards at you, while spinning in the opposite direction to the ring. So you have to avoid being shot by clockwise-rotating alternating laser fire AND by anticlockwise-rotating accelerating alternating turret fire. Also, there are eight small solid platforms wandering through the area you're trapped in, which you also must not touch! But which can be used as cover!
YOU ARE IN THE MIDDLE OF A SEETHING MAELSTROM OF BLACK AND WHITE LASER FIRE AND INSTANT DEATH.
You need two entirely separate craniums to keep track of everything on the screen in this game, let alone stay alive, let alone keep shooting at the right thing. Hard? It's often enough to panic you into submission. And it's a long way from the end of the game.
It's true: it takes real dedication and the devotion of significant time to get good at Ikaruga. But put in the effort and it will start to yield. The game does play out exactly the same way every time, so it is possible to learn the patterns and respond with safe strategies - and after time passes, a perceptual transcend will occur and you can leave the "switching colour" business to an entirely autonomous part of your brain - then, you're in for some fun.
But finishing Ikaruga isn't even a tenth of the point of the game.
This is an arcade game. This is about SCORES.
Scoring
Points are accumulated by several obvious methods and some other, rather more cunning ones.
Firstly, you get points for shooting stuff. That's easy. Boss battles are subject to a time limit and you get bonus points for killing them quickly. Some areas of the game are set up so that if you kill everything REALLY quickly, extra enemies appear, so finding and taking advantage of these triggers is a must for maximum points.
Secondly, you get points for absorbing enemy fire. That's much more cunning, since it encourages you to 1) deliberately put yourself in harm's way and 2) take more time over killing some creatures in order to absorb more of their attacks. (For example, one of the last bosses attacks you so violently and powerfully that it is actually more profitable, points-wise, to sit still and absorb its attacks before killing it at the last second, than it is to kill it as quickly as possible for the time bonus. However, this is also INSANELY difficult and dangerous; very, very few people employ it as a tactic because the risk of death is just too great.) So it's a balancing act.
Thirdly and most importantly: you get points for chains.
Every enemy is either black or white. If you kill three black or white enemies in a row, you get a 100 point bonus. If you then kill three black or white enemies in a row, you get 200 points (2 chain). Keep up the chains (you can switch colours, but you must always kill stuff in threes) and the bonus builds to 25,600 points ("max chain"). Break the chain and the bonus goes back to 100 as before.
Once you realise this, something magical occurs. You take a look at the game through fresh eyes. And you realise that all the enemies in the game can be cunningly grouped into threes.
And that each level contains over a thousand individual enemies.
And that it is possible to complete every single level without "breaking chain".
Figuring out how to best do this is an amazingly tactical process. Some chains are easier to get than others; some require extremely sharp shooting. For the first time, will you discover situations in which it is not a good idea to simply hold down the fire button permanently.
This, then, is the true magic of Ikaruga. Once you start to play for chains, you begin to realise that each of the five levels is, in fact, incredibly carefully constructed, providing huge varieties of scoring opportunities for almost every level of player. There are truly unbelievable and highly profitable tactics possible all over these 25 minutes of play, and to find them all is not only challenging but hugely entertaining and rewarding.
If you have what it takes, Ikaruga will return to you fourfold everything you put into it.
And if that wasn't enough...
Then you add in the amazing "smart bomb" attack which you can use if you absorb enough enemy fire.
Then you discover that all this time you've been playing on Easy mode; and that Normal and Hard are totally different, even more tactical experiences where even higher scores are possible.
You unlock the shockingly difficult Prototype Mode, in which your smart bomb can be used multiple times in a row for devastatingly high-scoring attacks, and discover the highly amusing "Dot Eater!" rank, which can be obtained by surviving a whole level without touching the fire button.
You try out cooperative two-player mode.
You buy the "Ikaruga Appreciate" DVD, an official Treasure release containing three essentially perfect runs through the whole game: one for each difficulty level.
You find that you can use passwords to rank your scores alongside those of other people online.
You find the video of those guys who get all the way through Normal without losing a life or breaking chain.
You find the video of the lunatic who plays as two ships at once.
You download the soundtrack to your computer and find yourself humming it at work...
Useful links
http://www.ikaruga.co.uk/
http://video.google.com/videoplay?docid=-163280885783523408
http://maddox.xmission.com/c.cgi?u=ikaruga
or just Google for Ikaruga...