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

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

Optimization · Pure Optimization
Comic hospital tycoon optimized by room layouts and staffing.
Portal leans Optimization (Pure Optimization); Two Point Hospital leans Optimization (Pure Optimization).
Portal leans clearly harder on execution.
Portal
Portal placement timing modest.
Two Point Hospital
no reflex
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.
Two Point Hospital
no adversary
Two Point Hospital leans clearly harder on variance.
Portal
Deterministic chambers; no randomness.
Two Point Hospital
patient illness mix
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.
Two Point Hospital
room layouts, staffing, training
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.