When you level up, the dungeon levels up. Difficult dungeons have tougher monsters and rare items, which should give players a reason to revisit old worlds.
Chaos Rings also has a character customization system where players use genetic data. Enemies drop genes. Equip these to use special skills like Cocytus, an aqua magic spell that deer in Chaos Rings have.
Square Enix producer Takehiro Ando says Chaos Rings, like most iPhone apps, is smoother on an iPhone 3GS. However, it works fine on a launch iPhone and any model iPod touch. Chaos Rings comes out this week worldwide.