head to head
Napoleon: Total War asks more than Portal, and the gap is reads.

Optimization · Pure Optimization
Grand strategy and line-infantry battles across the Napoleonic Wars.

Optimization · Pure Optimization
The portal-gun puzzle game whose solutions are everything.
Napoleon: Total War leans Optimization (Pure Optimization); Portal leans Optimization (Pure Optimization).
Portal leans a little harder on execution, though the gap is small.
Napoleon: Total War
Real-time battle micro under pressure
Portal
Portal placement timing modest.
Napoleon: Total War leans clearly harder on reads.
Napoleon: Total War
Multiplayer battles involve feints; campaign AI is mappable
Portal
No adversary modeling player.
Napoleon: Total War leans clearly harder on variance.
Napoleon: Total War
Morale swings and fog of war
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.
Napoleon: Total War
Campaign economy, army composition, and line tactics
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.