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 · Light / Casual
A first-person mystery about a fire lookout in a Wyoming forest.

Optimization · Light / Casual
A gorgeous first-person mystery about piecing together a boy's disappearance.
Firewatch leans Optimization (Light / Casual); The Vanishing of Ethan Carter leans Optimization (Light / Casual).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Firewatch
Walking and radio dialogue only.
The Vanishing of Ethan Carter
Walking and looking, nothing more
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Firewatch
No adaptive opposition.
The Vanishing of Ethan Carter
No opponent
The Vanishing of Ethan Carter leans a little harder on variance, though the gap is small.
Firewatch
Minor environmental discoveries.
The Vanishing of Ethan Carter
The mystery is hidden only until discovered
The Vanishing of Ethan Carter leans a little harder on optimization, though the gap is small.
Firewatch
Few systems to optimize.
The Vanishing of Ethan Carter
Reconstructing event sequences is light deduction
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.