head to head
Neither is simply harder - they are hard in different places. Fallout: New Vegas demands more execution; Prison Architect demands more variance.

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

Optimization · Pure Optimization
Designing a functional prison where security infrastructure and inmate need management prevent catastrophic failure.
Fallout: New Vegas leans Optimization (Pure Optimization); Prison Architect leans Optimization (Pure Optimization).
Fallout: New Vegas leans clearly harder on execution.
Fallout: New Vegas
Shooter inputs with VATS assist
Prison Architect
Layout design is deliberate; no twitch demands
Fallout: New Vegas leans a little harder on reads, though the gap is small.
Fallout: New Vegas
Scripted factions and enemies
Prison Architect
Prisoner behaviour is scripted around needs and contraband rules
Prison Architect leans clearly harder on variance.
Fallout: New Vegas
Some loot and crit RNG
Prison Architect
Riots and smuggling attempts introduce meaningful hidden threats
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
Prison Architect
Guard routing, cell ratios, and utility networks are deeply 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.