head to head
Kingdom Hearts Birth by Sleep asks more than Grand Theft Auto V, and the gap is optimization.

Execution · Practiced Mastery
Sandbox crime playground spanning shooting, driving, and a persistent online economy.

Optimization · Practiced Mastery
A PSP prequel following three keyblade wielders with a deep command-melding build system.
Grand Theft Auto V leans Execution (Practiced Mastery); Kingdom Hearts Birth by Sleep leans Optimization (Practiced Mastery).
Kingdom Hearts Birth by Sleep leans a little harder on execution, though the gap is small.
Grand Theft Auto V
Driving and shooting demand decent inputs.
Kingdom Hearts Birth by Sleep
Dodge timing against brutal secret bosses
Grand Theft Auto V leans a little harder on reads, though the gap is small.
Grand Theft Auto V
Online PvP exists but mostly gear/positioning, not modeling.
Kingdom Hearts Birth by Sleep
Pattern-based bosses, no adaptation
Grand Theft Auto V leans a little harder on variance, though the gap is small.
Grand Theft Auto V
Some mission and lobby randomness.
Kingdom Hearts Birth by Sleep
Command melding outcomes are documented
Kingdom Hearts Birth by Sleep leans clearly harder on optimization.
Grand Theft Auto V
Heists, money loops, builds learnable.
Kingdom Hearts Birth by Sleep
Command deck melding largely solves the game
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.