head to head
Neither is simply harder - they are hard in different places. Portal demands more execution; Romance of the Three Kingdoms XIV demands more variance.

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

Optimization · Pure Optimization
A grand strategy game of conquering ancient China by managing hundreds of officers and painting the map your color.
Portal leans Optimization (Pure Optimization); Romance of the Three Kingdoms XIV leans Optimization (Pure Optimization).
Portal leans clearly harder on execution.
Portal
Portal placement timing modest.
Romance of the Three Kingdoms XIV
Turn-based menus, zero dexterity
Romance of the Three Kingdoms XIV leans a little harder on reads, though the gap is small.
Portal
No adversary modeling player.
Romance of the Three Kingdoms XIV
AI warlords follow learnable behavior patterns
Romance of the Three Kingdoms XIV leans clearly harder on variance.
Portal
Deterministic chambers; no randomness.
Romance of the Three Kingdoms XIV
Officer events and AI moves add light fog
Romance of the Three Kingdoms XIV leans a little harder on optimization, though the gap is small.
Portal
Pure puzzle-solving optimization.
Romance of the Three Kingdoms XIV
Territory painting, officer assignment, and logistics are deeply solvable
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.