head to head
Portal asks more than FAR: Lone Sails, and the gap is optimization.

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

Optimization · Pure Optimization
The portal-gun puzzle game whose solutions are everything.
FAR: Lone Sails leans Optimization (Pure Optimization); Portal leans Optimization (Pure Optimization).
Portal leans clearly harder on execution.
FAR: Lone Sails
Light platforming and timely lever pulls
Portal
Portal placement timing modest.
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
Portal
No adversary modeling player.
FAR: Lone Sails leans a little harder on variance, though the gap is small.
FAR: Lone Sails
Mostly fixed obstacles, minor unknowns first run
Portal
Deterministic chambers; no randomness.
Portal leans clearly harder on optimization.
FAR: Lone Sails
Fuel management and ship-routine efficiency are the game
Portal
Pure puzzle-solving optimization.
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.