head to head
Neither is harder. They score identically on all four axes, so the difference between them is in kind, not degree.

Variance · Light / Casual
A short, unsettling visual novel about intrusive thoughts with no skill test.

Variance · Light / Casual
A kinetic visual novel that tests nothing beyond willingness to read.
Milk Inside a Bag of Milk Inside a Bag of Milk leans Variance (Light / Casual); Nekopara Vol. 3 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.
Milk Inside a Bag of Milk Inside a Bag of Milk
no physical skill demand at all
Nekopara Vol. 3
Clicking through text has no physical demand
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Milk Inside a Bag of Milk Inside a Bag of Milk
no opponent of any kind
Nekopara Vol. 3
No opponent of any kind
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Milk Inside a Bag of Milk Inside a Bag of Milk
branching text has minor unpredictability
Nekopara Vol. 3
The story is fixed; nothing hidden but unread pages
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Milk Inside a Bag of Milk Inside a Bag of Milk
barely any systems to solve
Nekopara Vol. 3
Nearly kinetic novel - no meaningful choices 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.