head to head
Neither is harder. They score identically on all four axes, so the difference between them is in kind, not degree.

Optimization · Practiced Mastery
Gentle minigame variety - flying, potions, duels - with no demanding axis.

Optimization · Practiced Mastery
A gag-driven platformer testing little beyond collectible patience.
Harry Potter and the Half-Blood Prince leans Optimization (Practiced Mastery); The Simpsons Game leans Optimization (Practiced Mastery).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Harry Potter and the Half-Blood Prince
Quidditch ring-chasing and duel timing are gentle
The Simpsons Game
Simple platforming and character-power 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 Half-Blood Prince
Duelling NPCs follow simple fixed patterns
The Simpsons Game
Parody enemies are jokes on rails
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 Half-Blood Prince
Hogwarts tasks are scripted and repeatable
The Simpsons Game
Levels are fixed gag sequences
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Harry Potter and the Half-Blood Prince
Potion-stirring sequences and castle routing are lightly solvable
The Simpsons Game
Character-ability puzzles and collectibles are lightly solvable
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.