Engineering puzzle · Zachtronics, 2017
Opus Magnum
Build alchemical machines from arms and tracks to make potions. Every puzzle has countless solutions, and graphs show how yours compares.
Puzzle profile
What you do
Place mechanical arms and program their moves to assemble molecules, then optimise for cost, speed or size.
Who it suits
Engineers, programmers and anyone who loves building machines.
The first lock
You build a tiny machine that makes salt. It works, and you immediately want to make it faster.
Deeper locks
Puzzles grow complex, but there is never one right answer. Comparing your score is addictive.
When you are stuck
Any working solution is fine. Move on and come back to optimise.
Opens easily
- Endless creative solutions
- Very fair
- Satisfying to watch
Sticks a little
- PC and Mac only
- Can feel like work
The score
Overall 4.7 out of 5 · how we score
Verdict
The friendliest engineering puzzle. Build, watch, improve.
Written by the Copper Key desk. Updated 25 October 2026. Facts checked against publisher and store pages at that date.