head to head
Neither is harder. They score identically on all four axes, so the difference between them is in kind, not degree.

Execution · Pure Mechanics
Heavy first-person gunplay testing aim, with positional prediction in multiplayer.

Execution · Pure Mechanics
Arcade streetball testing trick-combo execution and baiting human defenders.
Killzone 3 leans Execution (Pure Mechanics); NBA Street Homecourt leans Execution (Pure Mechanics).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Killzone 3
Weighty gunplay still demands aim and recoil control
NBA Street Homecourt
Trick-string timing and gamebreaker chains demand fast hands
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Killzone 3
Multiplayer opponents flank and bait; campaign AI is scripted
NBA Street Homecourt
Versus humans, baiting steals and blocks is real prediction
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Killzone 3
Spawns and spread inject limited randomness
NBA Street Homecourt
Mild bounce and AI randomness
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Killzone 3
Map control, loadouts and class roles structure multiplayer
NBA Street Homecourt
Trick-point economy toward gamebreakers rewards planning
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.