head to head
Neither is simply harder - they are hard in different places. Fallout: New Vegas demands more execution; Silent Storm: Sentinels demands more reads.

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

Optimization · Pure Optimization
A turn-based tactics game about squad positioning in destructible WWII environments.
Fallout: New Vegas leans Optimization (Pure Optimization); Silent Storm: Sentinels leans Optimization (Pure Optimization).
Fallout: New Vegas leans clearly harder on execution.
Fallout: New Vegas
Shooter inputs with VATS assist
Silent Storm: Sentinels
Turn-based, no physical aiming demands on player
Silent Storm: Sentinels leans clearly harder on reads.
Fallout: New Vegas
Scripted factions and enemies
Silent Storm: Sentinels
AI scripted but tactical positioning resembles light prediction
Silent Storm: Sentinels leans clearly harder on variance.
Fallout: New Vegas
Some loot and crit RNG
Silent Storm: Sentinels
Hit chances and destructible cover add real randomness
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Fallout: New Vegas
Faction routing, perks, builds heavily rewarded
Silent Storm: Sentinels
Squad builds, positioning and turn economy decide battles
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.