head to head
Neither is simply harder - they are hard in different places. Oriental Empires demands more reads; Portal demands more execution.

Optimization · Pure Optimization
A 4X strategy game testing empire economy, tech, and military planning.

Optimization · Pure Optimization
The portal-gun puzzle game whose solutions are everything.
Oriental Empires leans Optimization (Pure Optimization); Portal leans Optimization (Pure Optimization).
Portal leans clearly harder on execution.
Oriental Empires
Turn-based commands need no twitch precision
Portal
Portal placement timing modest.
Oriental Empires leans clearly harder on reads.
Oriental Empires
Multiplayer rewards anticipating rivals, but AI is scripted
Portal
No adversary modeling player.
Oriental Empires leans clearly harder on variance.
Oriental Empires
Combat and event randomness, mostly bounded
Portal
Deterministic chambers; no randomness.
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Oriental Empires
Economy, tech, and army development decide empires
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.