head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is variance, and it is a single point.

Optimization · Pure Optimization
The archetypal idle game where optimal purchase order is the entire skill.

Optimization · Pure Optimization
A classic management sim about building profitable, animal-friendly zoo exhibits.
Cookie Clicker leans Optimization (Pure Optimization); Zoo Tycoon leans Optimization (Pure Optimization).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Cookie Clicker
Clicking is optional past the early game
Zoo Tycoon
Mouse-driven building, no time pressure
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Cookie Clicker
No opponent
Zoo Tycoon
No opponents
Cookie Clicker leans a little harder on variance, though the gap is small.
Cookie Clicker
Golden cookie timing randomness
Zoo Tycoon
Animal needs are deterministic once learned
Cookie Clicker leans a little harder on optimization, though the gap is small.
Cookie Clicker
Purchase order and ascension math are the game
Zoo Tycoon
Exhibit suitability, finances, guest flow are solvable systems
A matching score does not mean a matching test. Two games can both sit at 10 on execution and demand completely different things of you - which is why the reasoning above matters more than the number beside it.