head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is reads, and it is a single point.

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

Optimization · Pure Optimization
A landmark strategy game combining a turn-based campaign for control of Rome with massive real-time battles.
Napoleon: Total War leans Optimization (Pure Optimization); Rome: Total War leans Optimization (Pure Optimization).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Napoleon: Total War
Real-time battle micro under pressure
Rome: Total War
Real-time battle micro rewards quick unit handling
Napoleon: Total War leans a little harder on reads, though the gap is small.
Napoleon: Total War
Multiplayer battles involve feints; campaign AI is mappable
Rome: Total War
Optional multiplayer battles; campaign AI is mappable
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Napoleon: Total War
Morale swings and fog of war
Rome: Total War
Diplomacy and AI moves add modest fog
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
Rome: Total War
Campaign economy, recruitment, and battle tactics are 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.