I turned browser cookie counts into game currency - meet Crumbongo

Crumbongo started from a pretty stupid little question:

What if the number of accessible cookies on the website you're visiting could become game currency?

So I built it.

Crumbongo is a tiny local Chrome game where you choose a website, let the extension count the accessible cookie records for that site, and turn only that number into game rewards.

No cookie names or values are used for gameplay.

From a tiny experiment to an actual little game

The first version was basically:

choose a website;
check its accessible cookie count;
harvest that number into a Cookie Jar;
spend the cookies on Bongo.

Then I kept building on top of it.

Crumbongo now has:

a level and progression system;
pixel-art cosmetics;
multiple habitats;
companions;
local statistics;
Monkey Climb;
Cookie Stack.

The whole thing still lives inside a Chrome extension popup.

The technical side

Crumbongo is deliberately small.

There is no React, TypeScript, Vite, game engine, backend or framework involved.

It's built with:

vanilla JavaScript;
HTML;
CSS;
Chrome Extension APIs;
requestAnimationFrame for the minigames;
chrome.storage.local for persistent game progress.

The minigames are built with regular DOM elements and CSS rather than Canvas.

That constraint became part of the fun: figuring out how far I could push a tiny extension popup without turning the project into something much larger.

Local by design

Because the core mechanic involves browser cookies, I wanted the privacy model to be extremely clear.

Crumbongo requests access one site at a time.

For gameplay it only uses the number of accessible cookie records returned for that site.

It does not:

store or transmit cookie names;
store or transmit cookie values;
modify or delete browser cookies;
use an account system;
use analytics or tracking;
send gameplay data to a backend.

Game progress stays locally in the browser.

The game-design part became more interesting than I expected

Once I added progression, I realized the cookie mechanic could support much more than a simple counter.

Cookies became a resource.

The Cookie Jar became something you wanted to grow.

Levels started unlocking things.

Cosmetics gave the currency a purpose.

Habitats and companions made Bongo's world feel like it was expanding.

Then the minigames gave players another way to interact with the same economy.

One of the hardest parts wasn't implementing features. It was deciding when something technically worked but still didn't feel right.

For example, Cookie Stack originally allowed the tower to grow too tall. It worked perfectly from a programming perspective, but after actually playing it, the next catch became unfair.

So the tower now clears after five pieces.

Tiny adjustment, much better game.

AI-assisted development

I also used AI tools during development, particularly Codex as a coding assistant and generative tools for parts of the visual exploration.

My workflow wasn't "prompt -> finished game".

It was usually:

define a specific change -> implement -> test manually -> inspect screenshots -> adjust -> repeat

AI was extremely useful for implementation speed, but decisions about progression, balance, visual positioning, what to remove, and whether something actually felt good still came from repeatedly using the game.

That part ended up being one of my favorite lessons from the project.