head to head
Neither is simply harder - they are hard in different places. Portal demands more execution; Rise of the Golden Idol demands more variance.

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

Optimization · Pure Optimization
A successor deduction game demanding systematic elimination across interconnected mystery tableaux.
Portal leans Optimization (Pure Optimization); Rise of the Golden Idol leans Optimization (Pure Optimization).
Portal leans clearly harder on execution.
Portal
Portal placement timing modest.
Rise of the Golden Idol
Interface identical to predecessor; no physical demands
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.
Rise of the Golden Idol
Scripted mystery scenes have no adaptive opponent
Rise of the Golden Idol leans clearly harder on variance.
Portal
Deterministic chambers; no randomness.
Rise of the Golden Idol
Hidden roles and motives form layered investigative uncertainty
Rise of the Golden Idol leans clearly harder on optimization.
Portal
Pure puzzle-solving optimization.
Rise of the Golden Idol
Closed-world deduction chain converges to exactly one correct answer per scene
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.