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 · Pure Mechanics
Linear military FPS about resisting an occupation of the United States.

Execution · Pure Mechanics
A gory budget FPS testing twitch aim through linear scripted firefights.
Homefront leans Execution (Pure Mechanics); Soldier of Fortune: Payback 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.
Homefront
Standard shooter gunplay carries the campaign
Soldier of Fortune: Payback
Twitch gunfights against aggressive AI are the core
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Homefront
Multiplayer adds some human prediction
Soldier of Fortune: Payback
Multiplayer existed but campaign AI never adapts
Homefront leans a little harder on variance, though the gap is small.
Homefront
Scripted setpieces, little randomness
Soldier of Fortune: Payback
Linear levels hold few surprises
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Homefront
Modest loadout and map knowledge layer
Soldier of Fortune: Payback
Loadout picks add only a thin 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.