|A beginning position...|
Solving the puzzle means using all the atoms to form a molecule. It's rarely simple, but the puzzles are mostly small enough that there are a limited number of possible moves. Some trial and error is generally enough to overcome a position that has you stumped. Also, each puzzle has a name that provides a minor hint.
|...and completed molecule.|
The game starts you out with a limited set of simple puzzles, then opens up more complex problems as you proceed. Solving one puzzle opens up access to others, and at certain intervals new mechanics are added, such as the ability to split bonds or create double bonds.
|The overview screen. Solving a puzzle reveals any adjacent unsolved puzzles.|