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 guided comedy showcase that tests nothing beyond following prompts.

Optimization · Light / Casual
A first-person mystery about a fire lookout in a Wyoming forest.
Aperture Desk Job leans Optimization (Light / Casual); Firewatch 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.
Aperture Desk Job
Pressing prompted buttons is the entire physical demand
Firewatch
Walking and radio dialogue only.
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Aperture Desk Job
Fully scripted comedy with no opponent
Firewatch
No adaptive opposition.
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Aperture Desk Job
One linear ride, identical every time
Firewatch
Minor environmental discoveries.
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Aperture Desk Job
Nothing to solve - follow the prompts
Firewatch
Few systems to optimize.
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.