head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is optimization, 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 classic point-and-click adventure where solving inventory puzzles is the entire challenge.
Firewatch leans Optimization (Light / Casual); Grim Fandango Remastered 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.
Grim Fandango Remastered
no physical skill ceiling, point-and-click
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.
Grim Fandango Remastered
no opponents, puzzle-driven
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.
Grim Fandango Remastered
no meaningful randomness
Grim Fandango Remastered leans a little harder on optimization, though the gap is small.
Firewatch
Few systems to optimize.
Grim Fandango Remastered
item and dialogue puzzle logic solvable
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.