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

Execution · Practiced Mastery
The original 2003 WWII shooter built around cinematic squad set pieces.

Execution · Pure Mechanics
WWII shooter remembered for its Omaha Beach landing and tense rifle duels.
Call of Duty leans Execution (Practiced Mastery); Medal of Honor: Allied Assault 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.
Call of Duty
Aim and reaction carry the scripted firefights
Medal of Honor: Allied Assault
classic FPS aim, leaning, and sniping
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Call of Duty
Light multiplayer prediction; campaign AI is scripted
Medal of Honor: Allied Assault
historic multiplayer scene rewarded outguessing humans
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Call of Duty
Some spawn and hit unpredictability
Medal of Honor: Allied Assault
scripted ambushes surprise only once
Call of Duty leans a little harder on optimization, though the gap is small.
Call of Duty
Memorising set pieces and weapon positions
Medal of Honor: Allied Assault
encounter memorization, especially Omaha Beach
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.