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
A 1977 timing test - lead the moving target and outscore the other gun.

Execution · Pure Mechanics
Linear military FPS about resisting an occupation of the United States.
Air-Sea Battle leans Execution (Pure Mechanics); Homefront 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.
Air-Sea Battle
Timing shots on moving targets is the entire game
Homefront
Standard shooter gunplay carries the campaign
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Air-Sea Battle
Head-to-head play adds slight outguessing of the other gunner
Homefront
Multiplayer adds some human prediction
Homefront leans a little harder on variance, though the gap is small.
Air-Sea Battle
Target patterns cycle predictably
Homefront
Scripted setpieces, little randomness
Homefront leans a little harder on optimization, though the gap is small.
Air-Sea Battle
Learning target speeds and angles is shallow but real
Homefront
Modest loadout and map knowledge 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.