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
A third-person tower defense about funneling orc hordes into gleefully lethal trap corridors.

Optimization · Pure Optimization
A tactical squad shooter where positioning and probability management outweigh raw aim.
Orcs Must Die! 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.
Orcs Must Die!
Active shooting supplements the traps
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.
Orcs Must Die!
Orc waves follow fixed paths
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.
Orcs Must Die!
Minor wave composition randomness
The Bureau: XCOM Declassified
cover-based hit chances are randomized
Orcs Must Die! leans a little harder on optimization, though the gap is small.
Orcs Must Die!
Trap placement and kill-corridor economics are the 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.