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 · Light / Casual
Tests nothing competitive - an authored interactive memoir to experience.

Variance · Light / Casual
A short, unsettling visual novel about intrusive thoughts with no skill test.
If Found... leans Optimization (Light / Casual); Milk Inside a Bag of Milk Inside a Bag of Milk leans Variance (Light / Casual).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
If Found...
Erasing pages takes no skill by design
Milk Inside a Bag of Milk Inside a Bag of Milk
no physical skill demand at all
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
If Found...
No opponent in a linear memoir
Milk Inside a Bag of Milk Inside a Bag of Milk
no opponent of any kind
Milk Inside a Bag of Milk Inside a Bag of Milk leans a little harder on variance, though the gap is small.
If Found...
Fully authored with nothing random
Milk Inside a Bag of Milk Inside a Bag of Milk
branching text has minor unpredictability
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
If Found...
Nothing to solve - the story simply unfolds
Milk Inside a Bag of Milk Inside a Bag of Milk
barely any systems to solve
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.