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 · Pure Optimization
Quiet side-scrolling journey piloting a land-ship across a dried-out sea.

Optimization · Pure Optimization
Coordinating three characters through fixed object-logic puzzles.
FAR: Lone Sails leans Optimization (Pure Optimization); The Cave leans Optimization (Pure Optimization).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
FAR: Lone Sails
Light platforming and timely lever pulls
The Cave
Undemanding platforming with no timing pressure
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
FAR: Lone Sails
No opponent of any kind
The Cave
No adversary - a narrating cave is not a mind
The Cave leans a little harder on variance, though the gap is small.
FAR: Lone Sails
Mostly fixed obstacles, minor unknowns first run
The Cave
Each character's section is unknown on first descent
The Cave leans a little harder on optimization, though the gap is small.
FAR: Lone Sails
Fuel management and ship-routine efficiency are the game
The Cave
Three-character object-shuffling puzzles are the whole game
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.