head to head
Neither is simply harder - they are hard in different places. Fallout: New Vegas demands more execution; Sherlock Holmes: Crimes & Punishments demands more variance.

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

Optimization · Pure Optimization
A detective adventure about gathering evidence and assembling deduction chains across six cases.
Fallout: New Vegas leans Optimization (Pure Optimization); Sherlock Holmes: Crimes & Punishments leans Optimization (Pure Optimization).
Fallout: New Vegas leans clearly harder on execution.
Fallout: New Vegas
Shooter inputs with VATS assist
Sherlock Holmes: Crimes & Punishments
Minor minigames, no real dexterity ceiling
Fallout: New Vegas leans a little harder on reads, though the gap is small.
Fallout: New Vegas
Scripted factions and enemies
Sherlock Holmes: Crimes & Punishments
Suspects are scripted, nothing adapts to you
Sherlock Holmes: Crimes & Punishments leans clearly harder on variance.
Fallout: New Vegas
Some loot and crit RNG
Sherlock Holmes: Crimes & Punishments
Clues are hidden but fixed until discovered
Fallout: New Vegas leans a little harder on optimization, though the gap is small.
Fallout: New Vegas
Faction routing, perks, builds heavily rewarded
Sherlock Holmes: Crimes & Punishments
Deduction chains have correct solvable answers
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.