head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is execution, 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 fixed-solution puzzle adventure where finding the right inventory combination unlocks every obstacle.
Cookie Clicker leans Optimization (Pure Optimization); The Secret of Monkey Island leans Optimization (Pure Optimization).
The Secret of Monkey Island leans a little harder on execution, though the gap is small.
Cookie Clicker
Clicking is optional past the early game
The Secret of Monkey Island
Clicking inventory items demands no twitch skill whatsoever
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
The Secret of Monkey Island
No adaptive opponent; all puzzles are fixed and authored
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Cookie Clicker
Golden cookie timing randomness
The Secret of Monkey Island
Some hidden items require exploration but solutions are invariant
Cookie Clicker leans a little harder on optimization, though the gap is small.
Cookie Clicker
Purchase order and ascension math are the game
The Secret of Monkey Island
Correct item combinations and dialogue chains fully determine progress
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.