Zero Sum

You failed math class. Math didn't forget.

Zero Sum is a twin-stick shooter drawn entirely in scratchy pencil on paper. The enemies ARE the numbers and your weapons ARE the math. No health bars. No hit points. Just raw arithmetic violence.

A "48" is charging at you. You fire ÷2. Now it's "24". Three more shots. "12," "6," "3." Switch to minus. Bang. Bang. Bang. Zero. Gone. Next.

That was the easy part.

Your Arsenal Is Unconventional

Forget guns. You carry operators. Minus and plus are your reliable sidearms. Rapid-fire, precise, boring, until they save your life. Division is a rifle that rips enemies in half. The square root shotgun turns a 999 into scattered rubble. Modulo is a grenade that nukes everything divisible by zero in one glorious blast.

Multiplication? A trap. An AoE effect that makes everything it touches worse, unless you're smart enough to set up the kill. And then there's Sigma, a lobbed vortex that sucks in every nearby enemy and crushes them into a single number whose value is the sum of everything it ate. Turn a scattered swarm of small fry into one big, easy-to-handle target.

Every operator changes the battlefield. Every shot requires a decision. Every clean kill and clever combo rewards bonus points. Integer splits, perfect roots, modulo blasts. The game knows when you're showing off.

The Numbers Fight Back

Enemies aren't just walking health bars in disguise. A prime number resists division. A factorial grows exponentially if you ignore it. Negatives flip your operators against you. Fast enemies have small values but come in swarms. Tanky enemies are triple-digit nightmares that shrug off subtraction. You don't just shoot, you solve.

Bosses That Would Make Mathematicians Sweat

Each boss is built around a mathematical concept that wants you dead (a small selection):

The Euler Owl 

• a wise creature on an exponential curve, firing Taylor series bullets that start slow and accelerate into screaming projectiles. Crack its numbered weak points before the expansion overwhelms you.

The Factorial Factory

• a monstrosity that launches factorial projectiles. 9! splits mid-air into 9 × 8 × 7 × 6 × …, a cascade of numbered shrapnel, each piece racing toward an anchor to recombine into something enormous. Kill the pieces before they merge or face the product.

The Pi Boss 

• a pie surrounded by digit shields. Each slice of pi must be dismantled in the right order, turning armor into weak points.

The Yin-Yang Boss 

• two spinning halves, one light, one dark. Kill the wrong side's weak points and the other goes berserk. Balance the harmony meter or drown in spawns.

The Prime Sieve Spider 

• an eight-legged horror whose web is a literal Sieve of Eratosthenes. Trapped in its grid of numbers, you must identify and destroy the composites while primes lurk as traps. Hit the wrong number and it breaks free as a real enemy. Clear the web to expose a leg joint. Destroy all eight to bring it down. Fail, and the entire web turns into a swarm.

Sketched by Hand, Animated Like a Fever Dream

Zero Sum looks like someone's notebook came alive and got angry. Enemies are pencil doodles on paper. It's not pixel art. It's not clean vector. It's the doodles you drew when you were bored in math class. Except these doodles want revenge.

Features

• 7 operator weapons, each with unique features, projectile behavior, and mathematical consequences

• Operator upgrades that evolve your arsenal: chain division, shotgun roots, area-of-effect modulo blasts and more

• Boss fights built around real mathematical concepts: exponentials, prime sieves, pi, harmonic balance, fractals and more

• Escalating enemy waves from single digits to six-figure monstrosities

• Twin-stick controls with mouse + keyboard or full gamepad support

• A skill ceiling made of mental math. The fastest players aren't the ones with the best reflexes, they're the ones who can factor 391 in their head while dodging the swarm