
"Even? Odd? Forget the math!" Enter the Collatz Conjecture—mathematics' greatest unsolved mystery—reimagined as a high-speed roguelike action game. Play as "Ichi," the muscle-brained magical girl, teleporting between lanes to smash back incoming numbers with charge shots!
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About
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?
Stats
Languages: English, Japanese, Simplified Chinese, Traditional Chinese
Reviews
[h1] 数学题也能当子弹打,但手残慎入♥ [/h1] 数学界未解之谜“考拉兹猜想”改编的动作肉鸽,实际玩起来就是高速弹幕射击加奇偶判断。飞来的数字分奇偶,你得在两条路线间瞬间闪现选边,偶数往上冲,奇数往下滑。打对了蓄力反击,打错了直接挨揍,后期弹幕密集到眼睛根本跟不上脑子。 机制确实够新鲜,把数学判断和动作反应绑在一起,打顺了那种“我居然能一边躲弹幕一边算奇偶”的错觉确实上头。每次倒下可以回“天堂”用货币永久强化属性,还能收集十几种魔导书武装自己,肉鸽那套成长循环是有的。 但说实话,难度曲线对新手不太友好。前期几轮基本就是被弹幕按在地上摩擦,手残党大概率在学会享受之前就先放弃了。配置要求倒是不高,4G内存加1G显存就能跑。不锁区,支持英文和日文。 we need chinse!!! [h1] 推此志也,虽与日月争光可也。 -- 屈原列传 司马迁♥ [/h1]
Динамичная экшен-RPG с элементами рогалика, где каждое число — ваш враг. Плюсы: Быстрый и напряжённый геймплей — молниеносные реакции и точные нажатия; Уникальная механика — простые правила, но сложный геймплей; Система улучшений — более 10 уникальных эффектов через гримуары. Минусы: Высокий уровень сложности — требует быстрой реакции и точности; Однопользовательский режим — нет мультиплеера; Повторяющийся контент — может быстро наскучить при частых смертях. Итог: понравится любителям быстрых и напряжённых игр. Захватывающий геймплей и уникальная механика делают EVEN OR ODD 1 увлекательной, несмотря на сложность и повторяющийся контент.
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Concurrent players on Steam, sampled daily since tracking started.
Убил чела и просто ничего не происходит, такое.
Momentum
Pace estimated from the game's recent review growth (our daily snapshots) at its own sales-per-review ratio — a momentum signal, not booked sales.
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