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.

Execution · Competitive PvP
Timing on the ball and outguessing the opposing player's tactics.

Execution · Competitive PvP
Simple-input arena fighting decided by baiting human defensive resources.
FIFA Soccer 06 leans Execution (Competitive PvP); Naruto Shippuden: Ultimate Ninja Storm Revolution 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.
FIFA Soccer 06
First-touch control and shot timing decide chances
Naruto Shippuden: Ultimate Ninja Storm Revolution
Combo and counter timing on intentionally simple inputs
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
FIFA Soccer 06
Human opponents vary attack patterns and bait tackles
Naruto Shippuden: Ultimate Ninja Storm Revolution
Baiting a human's substitutions and guard breaks matters
FIFA Soccer 06 leans a little harder on variance, though the gap is small.
FIFA Soccer 06
Bounces and keeper spills inject small randomness
Naruto Shippuden: Ultimate Ninja Storm Revolution
Fully visible fights with nothing hidden
FIFA Soccer 06 leans a little harder on optimization, though the gap is small.
FIFA Soccer 06
Squad selection and tactics reward preparation
Naruto Shippuden: Ultimate Ninja Storm Revolution
Team and awakening type picks are a shallow solvable layer
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.