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
Famously unforgiving ball control tested against human prediction in fast matches.

Execution · Pure Mechanics
A heavyweight sci-fi FPS pitting ISA soldiers against the Helghast with famously weighty gunfeel.
Kick Off 2 leans Execution (Pure Mechanics); Killzone 2 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.
Kick Off 2
The ball never sticks - constant trapping demands famously precise control
Killzone 2
Weighty gunplay punishes imprecise aim hard
Kick Off 2 leans a little harder on reads, though the gap is small.
Kick Off 2
Human matches reward predicting passes and tackle timing
Killzone 2
Multiplayer opponents adapt; campaign AI doesn't
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Kick Off 2
Pitch types and deflections add mild chaos
Killzone 2
Modest spawn and objective rotation noise
Killzone 2 leans a little harder on optimization, though the gap is small.
Kick Off 2
Set plays and formation knowledge sit underneath
Killzone 2
Class unlocks and map control are learnable
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.