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

Optimization · Pure Optimization
The original stealth assassination sim where each mission is a clockwork puzzle.

Optimization · Pure Optimization
A tactical squad shooter where positioning and probability management outweigh raw aim.
Hitman: Codename 47 leans Optimization (Pure Optimization); The Bureau: XCOM Declassified 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.
Hitman: Codename 47
Stiff aiming and unforgiving stealth movement
The Bureau: XCOM Declassified
cover shooting timing is moderate
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Hitman: Codename 47
Guards follow fixed scripted patrols
The Bureau: XCOM Declassified
alien AI is scripted, no adaptation
The Bureau: XCOM Declassified leans a little harder on variance, though the gap is small.
Hitman: Codename 47
First-run guard routes and triggers are unknown
The Bureau: XCOM Declassified
cover-based hit chances are randomized
Hitman: Codename 47 leans a little harder on optimization, though the gap is small.
Hitman: Codename 47
Learning the level clockwork is the whole game
The Bureau: XCOM Declassified
squad tactics and builds are 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.