head to head
Neither is simply harder - they are hard in different places. Knights of the Old Republic demands more variance; Portal demands more execution.

Optimization · Pure Optimization
A d20 Star Wars RPG where Force power selection and alignment routing define clear optimal paths.

Optimization · Pure Optimization
The portal-gun puzzle game whose solutions are everything.
Knights of the Old Republic leans Optimization (Pure Optimization); Portal leans Optimization (Pure Optimization).
Portal leans clearly harder on execution.
Knights of the Old Republic
Pseudo-turn-based d20 combat removes all twitch; timing aids exist but minor
Portal
Portal placement timing modest.
Knights of the Old Republic leans a little harder on reads, though the gap is small.
Knights of the Old Republic
All enemies follow scripted AI behaviour trees without player modelling
Portal
No adversary modeling player.
Knights of the Old Republic leans clearly harder on variance.
Knights of the Old Republic
Loot rolls and pazaak draws provide hidden information layers
Portal
Deterministic chambers; no randomness.
Knights of the Old Republic leans a little harder on optimization, though the gap is small.
Knights of the Old Republic
Force power selection, feat prerequisites and light/dark routing are systematically solvable
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.