head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is execution, and it is a single point.

Execution · Pure Mechanics
A heavyweight sci-fi FPS pitting ISA soldiers against the Helghast with famously weighty gunfeel.

Execution · Pure Mechanics
A PS4-era Killzone where a Shadow Marshal and his OWL drone fight through a divided Helghast city.
Killzone 2 leans Execution (Pure Mechanics); Killzone Shadow Fall leans Execution (Pure Mechanics).
Killzone 2 leans a little harder on execution, though the gap is small.
Killzone 2
Weighty gunplay punishes imprecise aim hard
Killzone Shadow Fall
Standard FPS aim and movement ceiling
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Killzone 2
Multiplayer opponents adapt; campaign AI doesn't
Killzone Shadow Fall
PvP modes reward predicting human players
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Killzone 2
Modest spawn and objective rotation noise
Killzone Shadow Fall
Some open level routes and spawn noise
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Killzone 2
Class unlocks and map control are learnable
Killzone Shadow Fall
OWL drone usage and loadouts optimize cleanly
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.