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 · Light / Casual
A gorgeous first-person mystery about piecing together a boy's disappearance.

Optimization · Light / Casual
A psychological detective adventure where a mind-palace reconstruction of events drives the small-town mystery.
The Vanishing of Ethan Carter leans Optimization (Light / Casual); Twin Mirror leans Optimization (Light / Casual).
The Vanishing of Ethan Carter leans a little harder on execution, though the gap is small.
The Vanishing of Ethan Carter
Walking and looking, nothing more
Twin Mirror
Exploration and dialogue; no dexterity test.
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
The Vanishing of Ethan Carter
No opponent
Twin Mirror
No opponent; the mystery is scripted.
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
The Vanishing of Ethan Carter
The mystery is hidden only until discovered
Twin Mirror
Branch consequences unknown on first playthrough.
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
The Vanishing of Ethan Carter
Reconstructing event sequences is light deduction
Twin Mirror
Mind-palace deduction scenes require assembling correct clue chains.
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.