Ikaruga is like no other shooter I've played. Despite my enjoyment of other excellent games like it, Ikaruga comes out on top. It's unfortunate that to describe why is so impressively difficult.
The challenge of the game and its convention-stretching inventive play combine to create an experience that is tricky to convey outside of its own genre, yet there are many things to say about Ikaruga. One can describe gameplay and give an assessment as Mike did, but I am to explain the game through the mental processes that take place while learning to play because it stimulates in such an interesting way.
At first I just wanted to watch what is the most visually appealing shooter I've seen. This proved lethal. Every time I advanced to a new stage, I quickly went through several lives as I focused on what Mike properly describes as its "[cyberpunk] aesthetic." The art and modeling is tight and focused, with nothing particularly overwrought. While at some points a bit mentally disturbing to consider in the heat of play, the graphics were never distracting. It was easy to concentrate on the game itself without getting overwhelmed by the incidental art once I set myself to the task.
The more insidious change from prior shooters, however, is the color polarity system. Mike's mention of predecessor Silhouette Mirage suggests this is not as original as it seems, but it was new to me. While the concept is quite readily understood, I found that the personal paradigmatic gameplay shift essential for doing well at Ikaruga was not immediately forthcoming. All my instincts and training from previous shooters led to an incessant assault on my conscious thought: AVOID ALL SHOTS! I had moderate success with that tactic until the first boss repeatedly tore me apart. The key, it seems, is to learn when to skirt and when to absorb enemy shots—a drastic retraining of reflexes honed by years of other shooters. Yes, it is in the player's best interest to fly right into enemy bullets!
Ikaruga throws new challenges at the player at every turn. Just as I became accustomed to the constant barrage of multi-colored shots, I was hit with solid walls of alternating color followed immediately by ever-expanding concentric circles, then twisting, zig-zagging streams, and no rest in sight! Being put in the middle of a swirling, rotating maelstrom of colors, interfering interwoven spirals hypnotic in their crossing and reversing mandalic floral patterns nearly drove me mad from disbelief: "How am I supposed to manage this?"
There is most definitely a "zone" that game players, whether video or athletic, can reach. It's a state of unthinking comprehension, action and simultaneous reaction—an almost tantric understanding of the surroundings or task at hand. Reaching this zone is probably the most helpful thing one can do while playing Ikaruga. Those whose problems achieving this state mirror mine will find that the more complex patterns will require a fair amount of practice. As Mike assesses, it is also the need to get into this zone that makes playing Ikaruga feel so much like playing a puzzle game.
Most puzzlers emphasize quick cognitive recognition skills. As new pieces appear on the field, the player must rapidly identify the unique attributes of the new piece as well as how it best fits into the existing layout. The appearance of enemy ships in Ikaruga may never be randomized (as in puzzle games), but unless the player already has an entrenched routine for each level, the same skills are stressed. The flood of black and white shots cause a constant switching between ship colors to stay alive, yet one must still consider how to unctuously dispose of all enemies. Constant action throughout the screen means a holistic view of the field is better than focusing on a single area. This perceptiveness and the corresponding demanding reactions to find the "best fit," are best achieved while in Mike's Zen-like zone, just as in puzzle games.
Despite my attempted eloquence, I feel that I have not managed to do Ikaruga justice. It is a wonderful, unique game with a stronger unified aesthetic than most and will require the hapless player to achieve a nigh-ascetic level of devotion to fully master. A superb work.