head to head
Grand Theft Auto: San Andreas asks more than Harry Potter and the Half-Blood Prince, and the gap is optimization.

Optimization · Practiced Mastery
A sprawling open-world crime epic with RPG-style character stats across a whole state.

Optimization · Practiced Mastery
Gentle minigame variety - flying, potions, duels - with no demanding axis.
Grand Theft Auto: San Andreas leans Optimization (Practiced Mastery); Harry Potter and the Half-Blood Prince leans Optimization (Practiced Mastery).
Grand Theft Auto: San Andreas leans a little harder on execution, though the gap is small.
Grand Theft Auto: San Andreas
Flying school and drive-bys need decent hands
Harry Potter and the Half-Blood Prince
Quidditch ring-chasing and duel timing are gentle
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Grand Theft Auto: San Andreas
Gang AI is scripted, never adaptive
Harry Potter and the Half-Blood Prince
Duelling NPCs follow simple fixed patterns
Grand Theft Auto: San Andreas leans a little harder on variance, though the gap is small.
Grand Theft Auto: San Andreas
Territory wars and traffic add light randomness
Harry Potter and the Half-Blood Prince
Hogwarts tasks are scripted and repeatable
Grand Theft Auto: San Andreas leans clearly harder on optimization.
Grand Theft Auto: San Andreas
Stats, gym, weapon skill, and routes reward systematic play
Harry Potter and the Half-Blood Prince
Potion-stirring sequences and castle routing 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.