About Curious Koko
Curious Koko is a free educational adventure game for children aged roughly 7 to 11, played in a web browser. There is a panda, a forest, eight worlds full of puzzles, and — underneath the fun — a deliberate curriculum.
What it actually is
Koko is a panda who lives in a treehouse at the edge of a scrolling forest. A child walks her around with the arrow keys, WASD, or an on-screen joystick on a tablet. Dotted around the forest are carved plaques — portals — and walking into one drops Koko into a themed world with a handful of short lessons disguised as puzzles.
Nothing about the structure is accidental. Each puzzle is two to four minutes long, because that is roughly how long a seven-year-old will stay with a maths problem before they want to be somewhere else. Finishing one pays out stars, coins and a themed crafting material, and the material is what unlocks the next thing to build. The maths is the price of admission to the part they actually came for.
Beyond the home forest there are six further realms, reached through rune-carved travel portals: a snowfield, a candy coast, a coral seabed, two school campuses, and a fairground. Each realm teaches skills the forest does not. There are also dress-up boutiques, playgrounds, and fairground stalls with no lessons in them at all, because a game that is only ever a test stops being a game.
Who makes it
Curious Koko is built and maintained by Saurabh Srivastava, an independent software developer. It began as something to build for my own child, who was working through grade-three Olympiad practice papers at the time and was markedly more enthusiastic about a panda than about a worksheet. The Olympiad Arena in the game is a direct descendant of that: real grade-three Maths and English Olympiad practice papers, with the method explained after every answer.
It is not the product of a studio, a publisher, or an education company. Every world, every puzzle, every question bank, and every line of code is written by one person. That is worth stating plainly, because it sets your expectations correctly: the game grows steadily rather than in big seasonal drops, and if something is wrong, there is exactly one person to email about it — see the contact page.
What it costs
Curious Koko is free to play. There is no subscription, no paid tier, no premium currency, and nothing in the game can be bought with real money. The coins, stars, gems and tickets a child earns exist only inside the game and have no cash value.
The running costs — hosting, database, domain — are covered by advertising displayed on the site's information pages. Ads are never placed inside gameplay, never over the game canvas, and never next to the joystick or a puzzle's answer buttons, because a child tapping an ad by mistake is bad for the child, bad for the advertiser, and against the rules of the ad network. How advertising works here, and what it means for your child's data, is set out in full in the privacy policy and summarised for parents on the parents' page.
How it is built
The game runs entirely in the browser — there is nothing to install, though it can be added to a tablet's home screen and will then launch full-screen like an app. It is built with TypeScript, React and the Phaser game engine, and hosted on Google Firebase.
One unusual detail: almost none of the artwork is a picture file. Koko herself, her walk animations, the trees, the water, the interiors of her treehouse and the sixty items of clothing in the wardrobe are all drawn in code at load time. This keeps the download small enough that the game starts quickly on an old school tablet over indifferent Wi-Fi, which is the device it most often has to run on.
Progress is saved locally in the browser first, so the game keeps working on a train or in a classroom with no connection. If you sign in, progress is mirrored to a database so it follows the child to another device.