head to head
Neither is simply harder - they are hard in different places. Age of Empires: Mythologies demands more reads; Fallout: New Vegas demands more execution.

Optimization · Pure Optimization
Turn-based economic and unit-counter planning across mythological factions.

Optimization · Pure Optimization
A faction-driven RPG-shooter where build and route planning shape every ending.
Age of Empires: Mythologies leans Optimization (Pure Optimization); Fallout: New Vegas leans Optimization (Pure Optimization).
Fallout: New Vegas leans clearly harder on execution.
Age of Empires: Mythologies
Turn-based input removes any dexterity test
Fallout: New Vegas
Shooter inputs with VATS assist
Age of Empires: Mythologies leans clearly harder on reads.
Age of Empires: Mythologies
Human multiplayer rewards some prediction; campaign AI is mappable
Fallout: New Vegas
Scripted factions and enemies
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Age of Empires: Mythologies
Fog of war hides enemy positions temporarily
Fallout: New Vegas
Some loot and crit RNG
Fallout: New Vegas leans a little harder on optimization, though the gap is small.
Age of Empires: Mythologies
Unit counters, economy and god powers reward deep planning
Fallout: New Vegas
Faction routing, perks, builds heavily rewarded
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.