head to head
Goat Simulator 3 asks more than Firewatch, and the gap is execution.

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

Execution · Light / Casual
Chaotic physics sandbox starring a goat.
Firewatch leans Optimization (Light / Casual); Goat Simulator 3 leans Execution (Light / Casual).
Goat Simulator 3 leans clearly harder on execution.
Firewatch
Walking and radio dialogue only.
Goat Simulator 3
Loose physics goat control
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.
Goat Simulator 3
No adaptive opponents
Goat Simulator 3 leans clearly harder on variance.
Firewatch
Minor environmental discoveries.
Goat Simulator 3
Glitchy emergent physics events
Goat Simulator 3 leans a little harder on optimization, though the gap is small.
Firewatch
Few systems to optimize.
Goat Simulator 3
Mutator and gear combo discovery
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.