Molecule: Chemistry Puzzle

A chemistry notebook. A handful of loose atoms. A formula to solve.

MOLECULE is a chemistry puzzle game with the look and feel of a hand-drawn
lab notebook. Every practical hands you a few atoms and a real compound to
build: drag, connect and fill every valence until the formula adds up. No
atoms left over. No extra bonds.

You start with H₂. You finish with caffeine.

— HOW TO PLAY —

Every atom has its own bonds to give: hydrogen one, oxygen two, nitrogen
three, carbon four. Drag one atom onto another to bond them and build the
exact structure of the compound.

It sounds easy with water. Wait until you reach aspirin.

Each practical gives you a move budget: the fewer moves you spend, the more
points you score. Add one bond too many and you get an atomic overload. Run
out of moves and you start over. No rush, no timer — just you, your head
and the notebook.

— 200 PRACTICALS, FROM SIMPLE TO IMPOSSIBLE —

200 real compounds, sorted by difficulty and unlocked one at a time.
Nothing here is made up: every molecule keeps the bonds and valences it has
in the real world, exactly as listed in the PubChem database.

You'll recognise plenty along the way:
- Water, oxygen, ammonia, carbon dioxide
- Methane, ethanol, acetone, acetic acid
- Benzene, toluene, phenol, naphthalene, glycerol
- Glycine, alanine, cysteine and other amino acids
- Vanillin, citric acid, nicotinamide
- Aspirin, paracetamol, caffeine

Inorganic and organic chemistry, covalent bonding and molecular structure,
without opening a textbook. By the time you solve the last practical,
you'll be able to draw half a dozen molecules from memory that used to be
nothing but names.

— A GAME WITH CHARACTER —

Squared paper, blue ink, ballpoint strokes. MOLECULE doesn't look like a
chemistry app: it looks like the notebook of the student who got bored in
class and started drawing in the margins. Every detail is hand-tuned, in
both light and dark mode.

- Score and personal best on every practical
- Progress saved automatically
- Shareable result card for your solutions
- Two minutes of instructions and you're playing
- Available in English, Spanish, French, German, Italian and Portuguese

— GENUINELY CLEAN —

No ads. No in-app purchases. No sign-up. No accounts. No permissions. No
internet connection: it's a fully offline game and it runs with no signal
at all, on the underground, on a plane or in the middle of nowhere.

We collect nothing about you, because the app doesn't even have the means
to send it. Your progress lives on your phone and nowhere else.

— WHO IS IT FOR? —

For anyone who enjoys a good puzzle, even if they haven't touched chemistry
since school: no prior knowledge needed, the rules fit on two screens and
you pick up the rest by playing.

For high school, GCSE, A-Level and AP Chemistry students who want valences,
bonds and structures to stick by playing rather than revising.

For chemistry teachers looking for five minutes of class that feel
different.

And for anyone who loves that feeling of staring at a screen, not seeing
the answer, staring a bit longer… and then suddenly seeing it.

Download MOLECULE and build your first molecule in under a minute.

Recent changes:
• New Support page in Settings: voluntary ways to help this notebook keep growing.
• Support for free by watching an ad, or treat the developer to a coffee or a pizza, or become a patron.
• None of it unlocks practicals or gives points: the notebook is the same for everyone. Supporters get a thank-you stamp on that page.