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
A top-down shoot-em-up testing aim and dodging against scripted alien waves.

Execution · Pure Mechanics
A late-90s mercenary FPS infamous for its graphic locational damage system.
Earth Defense Force leans Execution (Pure Mechanics); Soldier of Fortune 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.
Earth Defense Force
Top-down shooting and dodging are the core demand
Soldier of Fortune
Fast twitch aim against fragile enemies decides everything
Soldier of Fortune leans a little harder on reads, though the gap is small.
Earth Defense Force
Enemies are scripted waves, not adaptive
Soldier of Fortune
Multiplayer duels add a little human prediction
Earth Defense Force leans a little harder on variance, though the gap is small.
Earth Defense Force
Enemy spawn patterns add some unpredictability
Soldier of Fortune
Campaign layouts and spawns are fixed
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Earth Defense Force
Weapon management and positioning aid survival
Soldier of Fortune
Weapon choice and level routes are quickly learned
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.