head to head
Grand Theft Auto V asks more than Kirby's Block Ball, and the gap is reads.

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

Execution · Practiced Mastery
Breakout reflexes across four paddles with Kirby power timing.
Grand Theft Auto V leans Execution (Practiced Mastery); Kirby's Block Ball leans Execution (Practiced Mastery).
Kirby's Block Ball leans a little harder on execution, though the gap is small.
Grand Theft Auto V
Driving and shooting demand decent inputs.
Kirby's Block Ball
Four-paddle ball control and timed Kirby powers test reflexes
Grand Theft Auto V leans clearly harder on reads.
Grand Theft Auto V
Online PvP exists but mostly gear/positioning, not modeling.
Kirby's Block Ball
Blocks and bosses are fully scripted
Grand Theft Auto V leans a little harder on variance, though the gap is small.
Grand Theft Auto V
Some mission and lobby randomness.
Kirby's Block Ball
Ball physics are deterministic from paddle contact
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Grand Theft Auto V
Heists, money loops, builds learnable.
Kirby's Block Ball
Power usage and block routing reward stage knowledge
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.