For non-Ikaruga fans, the game's core concept is that the color of your ship determines who can damage you. If your enemy is the same color as you, your enemy's attacks won't damage you (in fact you can absorb their attacks). And inversely, if you and your enemy are different colors, their attacks will damage you.This is where the color-changing aspect comes into play.
This is simple in concept, but as Ikaruga fans will tell you, it's harder than it looks. Fortunately, you will be able to bring a friends with you, as this version of Ikaruga will feature online and offline co-op. So, get ready to have some color-changing fun when the game hits, and please, don't throw your controllers. They're not exactly cheap.