Codon Craft

Codon Craft is a logic puzzle game about building machines out of DNA. Four kilometres beneath the Pacific, the Lumen Archive holds the last library of life on Earth, with every species we managed to save stored as strands of DNA. Thousands drift in every day, and your machines decide where each one goes.

On a grid called the culture dish, you drag tracks into place and add readers and writers. A reader snips the first letter off a strand and sends it down a different path for each letter it finds. A writer adds a letter to the other end. Send healthy strands to the Vault, recycle the damaged ones, and repair the ones worth saving on the way through.

It starts with simple sorting and builds to copying and reversing strands, counting and comparing in binary, and checking strands for symmetry and balance. You never type a line of code, and you need no programming or biology background. Yet tracks, readers and writers can compute anything a computer can, given room, so every solution is an algorithm you can watch run.

Press Run to watch strands travel through your machine, then see it tested against many more. When one goes astray, you see what was expected beside what your machine produced, then replay that strand slowly, pause it, and spot exactly where it slipped. Try strands of your own on the Bench, and once a machine works, optimise it to use fewer parts.

Your guide is Dr Ada Franklin, curator of the Archive. She explains each new idea, cheers your good work and has strong views on the station canteen. When a machine loops forever, she might tell you: “It’s going round in circles. Relatable, but not helpful.” Stuck on a puzzle? Her notes offer hints one step at a time, whenever you want them.

Between puzzles, the Journal keeps the story so far and short notes on the real science behind it, from Barbara McClintock’s jumping genes to PCR and storing books in DNA. See it through, and the first lost species will grow again.

Try the opening puzzles before you buy. One in app purchase, the Full Archive, unlocks the rest permanently. There are no ads, subscriptions or timers, and every hint is included. The game plays offline, needs no account, and a save code moves your progress to another device.

Recent changes:
Behind the scenes:
• Anonymous play statistics (no personal data) to help us tune puzzles that are too hard
• Small fixes