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

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

Optimization · Pure Optimization
A pirate-themed action RPG sequel trading Gothic gloom for muskets, voodoo, and tropical islands.
Fallout: New Vegas leans Optimization (Pure Optimization); Risen 2: Dark Waters 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.
Fallout: New Vegas
Shooter inputs with VATS assist
Risen 2: Dark Waters
Clunky melee with dirty-trick interrupts; modest demands
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
Risen 2: Dark Waters
Scripted enemy behavior throughout
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Fallout: New Vegas
Some loot and crit RNG
Risen 2: Dark Waters
Light loot randomness only
Fallout: New Vegas leans a little harder on optimization, though the gap is small.
Fallout: New Vegas
Faction routing, perks, builds heavily rewarded
Risen 2: Dark Waters
Skill investment, voodoo builds, and quest order decide power
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.