head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is reads, and it is a single point.

Optimization · Pure Optimization
Claustrophobic horror about escaping a sealed apartment through nightmare worlds.

Optimization · Pure Optimization
A perk-driven sci-fi RPG won by flaw selection and dialogue routing.
Silent Hill 4: The Room leans Optimization (Pure Optimization); The Outer Worlds leans Optimization (Pure Optimization).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Silent Hill 4: The Room
Melee combat is simple and forgiving
The Outer Worlds
FPS-lite with time-dilation aim
The Outer Worlds leans a little harder on reads, though the gap is small.
Silent Hill 4: The Room
Ghosts patrol on fixed rules
The Outer Worlds
Scripted enemies
Silent Hill 4: The Room leans a little harder on variance, though the gap is small.
Silent Hill 4: The Room
Hauntings and layouts surprise only first time through
The Outer Worlds
Loot rolls, dialogue check variance
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Silent Hill 4: The Room
Escort routing and candle management are solvable
The Outer Worlds
Perks, flaws, dialogue routing rewarded
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.