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.

Variance · Systems & Chaos
Map-and-compass navigation through hidden dangers on a hostile mountain.

Optimization · Systems & Chaos
A wordless surreal exploration game about wandering a sleeping girl's dreamscapes.
Kholat leans Variance (Systems & Chaos); Yume Nikki leans Optimization (Systems & Chaos).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Kholat
Walking the mountain takes no dexterity
Yume Nikki
Just walking, no challenge on inputs
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Kholat
The presence stalks on randomised triggers, not a mind
Yume Nikki
No opponent of any kind
Kholat leans a little harder on variance, though the gap is small.
Kholat
Navigating by map coordinates with hidden danger zones
Yume Nikki
Random events and obscure unknown triggers
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Kholat
Landmark navigation and route memory converge with repetition
Yume Nikki
Mapping the dream worlds to find 24 effects
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.