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
A psychological horror RPG where a shut-in's dream world slowly cracks around a buried truth.

Optimization · Systems & Chaos
A wordless surreal exploration game about wandering a sleeping girl's dreamscapes.
Omori leans Optimization (Pure Optimization); 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.
Omori
Turn-based menus, no dexterity needed
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.
Omori
Scripted encounters throughout
Yume Nikki
No opponent of any kind
Yume Nikki leans a little harder on variance, though the gap is small.
Omori
Minor drop and emotion randomness
Yume Nikki
Random events and obscure unknown triggers
Omori leans a little harder on optimization, though the gap is small.
Omori
Emotion triangle and follow-ups are easily solvable
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.