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

Optimization · Pure Optimization
A Hitman-style Cold War stealth game about a KGB assassin working sandboxed kill missions.

Optimization · Pure Optimization
A faction-driven RPG-shooter where build and route planning shape every ending.
Alekhine's Gun leans Optimization (Pure Optimization); Fallout: New Vegas 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.
Alekhine's Gun
Timing takedowns matters less than planning them
Fallout: New Vegas
Shooter inputs with VATS assist
Fallout: New Vegas leans a little harder on reads, though the gap is small.
Alekhine's Gun
NPC routines are clockwork, never reactive learning
Fallout: New Vegas
Scripted factions and enemies
Alekhine's Gun leans a little harder on variance, though the gap is small.
Alekhine's Gun
First visits hide patrol routines and disguise rules
Fallout: New Vegas
Some loot and crit RNG
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Alekhine's Gun
Mapping routines and disguises reduces missions to solved puzzles
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.