head to head
Grand Theft Auto V asks more than Just Cause 2, and the gap is reads.

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

Execution · Practiced Mastery
A massive open-world sandbox built around grappling-hook and parachute chaos.
Grand Theft Auto V leans Execution (Practiced Mastery); Just Cause 2 leans Execution (Practiced Mastery).
Grand Theft Auto V leans a little harder on execution, though the gap is small.
Grand Theft Auto V
Driving and shooting demand decent inputs.
Just Cause 2
Grapple-parachute flow rewards handling skill
Grand Theft Auto V leans clearly harder on reads.
Grand Theft Auto V
Online PvP exists but mostly gear/positioning, not modeling.
Just Cause 2
Enemy AI never adapts
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Grand Theft Auto V
Some mission and lobby randomness.
Just Cause 2
Sandbox chaos varies moment to moment
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.
Just Cause 2
Chaos-point economy and settlement completion routing
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.