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

Optimization · Pure Optimization
A knowledge-based mystery solved by mapping a deterministic solar system.

Optimization · Pure Optimization
Zen sliding-droplet puzzler about clearing pearls in the fewest moves.
Outer Wilds leans Optimization (Pure Optimization); Quell leans Optimization (Pure Optimization).
Outer Wilds leans a little harder on execution, though the gap is small.
Outer Wilds
Light piloting, mostly forgiving
Quell
Swipes only; no timing pressure
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Outer Wilds
World is fixed; nothing adapts to you
Quell
No opponent exists
Outer Wilds leans a little harder on variance, though the gap is small.
Outer Wilds
Loop is deterministic once understood
Quell
Fully deterministic boards
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Outer Wilds
Pure knowledge puzzle - solve the system
Quell
Minimum-move sliding solutions are pure logic
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.