head to head
Neither is simply harder - they are hard in different places. Portal demands more execution; Samorost demands more variance.

Optimization · Pure Optimization
The portal-gun puzzle game whose solutions are everything.

Optimization · Pure Optimization
Poking a surreal contraption world until its hidden logic clicks.
Portal leans Optimization (Pure Optimization); Samorost leans Optimization (Pure Optimization).
Portal leans clearly harder on execution.
Portal
Portal placement timing modest.
Samorost
Clicking hotspots requires no dexterity
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Portal
No adversary modeling player.
Samorost
No opponent of any kind exists
Samorost leans clearly harder on variance.
Portal
Deterministic chambers; no randomness.
Samorost
Surreal solutions are hidden until experimented with
Portal leans clearly harder on optimization.
Portal
Pure puzzle-solving optimization.
Samorost
Each screen is a small solvable contraption
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.