head to head
Neither is simply harder - they are hard in different places. King Arthur II: The Role-Playing Wargame demands more variance; Portal demands more execution.

Optimization · Pure Optimization
A fantasy RTS-RPG hybrid solved through army composition and tactical planning.

Optimization · Pure Optimization
The portal-gun puzzle game whose solutions are everything.
King Arthur II: The Role-Playing Wargame leans Optimization (Pure Optimization); Portal leans Optimization (Pure Optimization).
Portal leans clearly harder on execution.
King Arthur II: The Role-Playing Wargame
Real-time battles need control but never twitch precision
Portal
Portal placement timing modest.
King Arthur II: The Role-Playing Wargame leans clearly harder on reads.
King Arthur II: The Role-Playing Wargame
Scripted campaign foes don't adapt to your habits
Portal
No adversary modeling player.
King Arthur II: The Role-Playing Wargame leans clearly harder on variance.
King Arthur II: The Role-Playing Wargame
Battle rolls and morale add bounded randomness
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.
King Arthur II: The Role-Playing Wargame
Army composition, hero builds and battle planning decide wins
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.