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

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

Optimization · Pure Optimization
A peaceful survival game about optimizing machines to terraform a dead planet.
Portal leans Optimization (Pure Optimization); The Planet Crafter leans Optimization (Pure Optimization).
Portal leans clearly harder on execution.
Portal
Portal placement timing modest.
The Planet Crafter
Walking and placing machines, no dexterity test
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.
The Planet Crafter
A dead planet offers no opposition
The Planet Crafter leans clearly harder on variance.
Portal
Deterministic chambers; no randomness.
The Planet Crafter
Wreck locations unknown until explored, then fixed
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Portal
Pure puzzle-solving optimization.
The Planet Crafter
Terraforming-index machine ratios are a solvable progression
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.