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.

Execution · Pure Mechanics
Treyarch's future-tech Call of Duty that anchored competitive console FPS.

Execution · Competitive PvP
Hardcore team shooter where one bullet kills and the HUD tells you nothing.
Call of Duty: Black Ops II leans Execution (Pure Mechanics); Insurgency leans Execution (Competitive PvP).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Call of Duty: Black Ops II
Snap aim and movement speed decide split-second gunfights
Insurgency
One-shot lethality rewards precise aim
Insurgency leans a little harder on reads, though the gap is small.
Call of Duty: Black Ops II
Human lobbies adapt rotations; pros mind-game spawns
Insurgency
Human squads flank and adapt each round
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Call of Duty: Black Ops II
Spawn flips and scorestreak chaos inject randomness
Insurgency
No killcam or HUD hides enemy positions
Call of Duty: Black Ops II leans a little harder on optimization, though the gap is small.
Call of Duty: Black Ops II
Pick-10 classes and streak economies reward optimization
Insurgency
Loadout points and objective route knowledge
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.