head to head
Neither is harder. They score identically on all four axes, so the difference between them is in kind, not degree.

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

Optimization · Light / Casual
A slow cinematic thriller that tests patience and attention, not skill.
Firewatch leans Optimization (Light / Casual); Fort Solis 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.
Fort Solis
Walking and occasional QTEs carry no real ceiling
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.
Fort Solis
A scripted thriller with no adversary to model
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Firewatch
Minor environmental discoveries.
Fort Solis
The mystery is fixed; only first-playthrough ignorance hides it
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Firewatch
Few systems to optimize.
Fort Solis
Light log-hunting is the only system to engage
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.