head to head
Neither is simply harder - they are hard in different places. Hotel Dusk: Room 215 demands more variance; Portal demands more execution.

Optimization · Pure Optimization
Noir DS adventure about interrogating hotel guests to unpick a mystery.

Optimization · Pure Optimization
The portal-gun puzzle game whose solutions are everything.
Hotel Dusk: Room 215 leans Optimization (Pure Optimization); Portal leans Optimization (Pure Optimization).
Portal leans clearly harder on execution.
Hotel Dusk: Room 215
Stylus puzzles need negligible dexterity
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.
Hotel Dusk: Room 215
Characters follow a fixed narrative script
Portal
No adversary modeling player.
Hotel Dusk: Room 215 leans clearly harder on variance.
Hotel Dusk: Room 215
Story info hidden until questioned out
Portal
Deterministic chambers; no randomness.
Portal leans clearly harder on optimization.
Hotel Dusk: Room 215
Choosing right dialogue and solving set puzzles
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.