head to head
Neither is simply harder - they are hard in different places. Fallout: New Vegas demands more execution; Galactic Civilizations II: Dread Lords demands more variance.

Optimization · Pure Optimization
A faction-driven RPG-shooter where build and route planning shape every ending.

Optimization · Pure Optimization
Space 4X where out-planning the galaxy's economy wins wars before they start.
Fallout: New Vegas leans Optimization (Pure Optimization); Galactic Civilizations II: Dread Lords leans Optimization (Pure Optimization).
Fallout: New Vegas leans clearly harder on execution.
Fallout: New Vegas
Shooter inputs with VATS assist
Galactic Civilizations II: Dread Lords
Turn-based; zero dexterity
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Fallout: New Vegas
Scripted factions and enemies
Galactic Civilizations II: Dread Lords
Acclaimed AI still follows mappable doctrines
Galactic Civilizations II: Dread Lords leans clearly harder on variance.
Fallout: New Vegas
Some loot and crit RNG
Galactic Civilizations II: Dread Lords
Galaxy generation and unexplored starts
Galactic Civilizations II: Dread Lords leans a little harder on optimization, though the gap is small.
Fallout: New Vegas
Faction routing, perks, builds heavily rewarded
Galactic Civilizations II: Dread Lords
Economy sliders, ship design, and expansion math dominate
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.