Beat a mathematical enigma with pure reflexes.

The Collatz Conjecture—an incredibly simple yet maddeningly complex puzzle that has baffled the world’s greatest minds for decades, derailing the lives of brilliant mathematicians.

While geniuses lose their minds at their desks, “Ichi,” the muscle-brained magical girl, takes on this unsolved mystery in the only way she knows how.

Monsters relentlessly fire “Magic Numbers” at you.

Instantly teleport between lanes—upper for even numbers [↑], lower for odd numbers [↓].

Read the incoming digits in a split second, charge your shot, and smash them back.

One wrong move in this extreme reflex battle can be fatal.

But when massive numbers finally collapse into a single “1,” Ichi’s magic spirals completely out of control.

Geniuses will keep fighting this unsolved mystery with their brains.

As for us? We’re taking it on with gamer reflexes.

◆ Brain-Melting "Even/Odd" Action

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Enemies will unleash a relentless barrage of numbers. Instantly determine if they are even or odd and strike back with the correct magic. Chain correct answers to multiply your power, reduce the enemy's number to "1", and obliterate them with a devastating Finisher!

◆ Perfect Parries & Just Defense

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Don't just take the hits. Read the trajectory of enemy attacks and strike back at the exact right moment to turn the tide of battle. When backed into a corner, unleash the "Auto-Parry" to survive impossible bullet hells.

◆ Death, Rebirth, and Grimoires

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Death is not the end. Return to "Heaven" and use your collected currency to permanently upgrade your stats. Discover and equip over 10 different Grimoires (magic books) with unique effects to continuously push your abilities to the limit.

◆ The Mystery of the Endless Calculation

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You play as "Ichi", an amnesiac protagonist. Why must she fight? And what truly awaits her at the end of this endless calculation...?

◆ 90 Achievements

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Track your mastery across 9 categories, including Max Combos, Highest Floor Reached, and Max Damage. Can you unlock all 90 achievements and leave your mark on the trajectory of this endless calculation?