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 · Competitive PvP
Analog-stick boxing testing punch precision and counter-baiting against human opponents.

Execution · Pure Mechanics
Heavy first-person gunplay testing aim, with positional prediction in multiplayer.
Fight Night 2004 leans Execution (Competitive PvP); Killzone 3 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.
Fight Night 2004
Analog punch control and block timing are the core test
Killzone 3
Weighty gunplay still demands aim and recoil control
Fight Night 2004 leans a little harder on reads, though the gap is small.
Fight Night 2004
Versus humans, baiting counters and feinting is genuine prediction
Killzone 3
Multiplayer opponents flank and bait; campaign AI is scripted
Killzone 3 leans a little harder on variance, though the gap is small.
Fight Night 2004
Outcomes follow inputs with little randomness
Killzone 3
Spawns and spread inject limited randomness
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Fight Night 2004
Stat training and stamina management add a planning layer
Killzone 3
Map control, loadouts and class roles structure multiplayer
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.