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 · Light / Casual
A casual licensed action game testing little beyond light co-op coordination.

Execution · Practiced Mastery
Linear postwar crime story driven by cover shootouts and atmosphere.
Harry Potter and the Goblet of Fire leans Execution (Light / Casual); Mafia II leans Execution (Practiced Mastery).
Mafia II leans a little harder on execution, though the gap is small.
Harry Potter and the Goblet of Fire
Simple co-op spell casting with generous timing
Mafia II
Cover shooting and fistfight timing
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Harry Potter and the Goblet of Fire
Enemies are fixed waves, no adaptation
Mafia II
Enemies are scripted
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Harry Potter and the Goblet of Fire
Collectible bean locations are fixed
Mafia II
Story missions are fixed
Mafia II leans a little harder on optimization, though the gap is small.
Harry Potter and the Goblet of Fire
Light card collection and spell upgrade choices
Mafia II
Modest; learning encounter layouts
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.