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

Optimization · Practiced Mastery
The genre-defining 3D open-world crime game set in Liberty City.

Execution · Practiced Mastery
Sandbox crime playground spanning shooting, driving, and a persistent online economy.
Grand Theft Auto III leans Optimization (Practiced Mastery); Grand Theft Auto V leans Execution (Practiced Mastery).
Grand Theft Auto V leans a little harder on execution, though the gap is small.
Grand Theft Auto III
Driving and clunky gunplay set a modest physical bar
Grand Theft Auto V
Driving and shooting demand decent inputs.
Grand Theft Auto V leans clearly harder on reads.
Grand Theft Auto III
Enemies are scripted; nothing models the player
Grand Theft Auto V
Online PvP exists but mostly gear/positioning, not modeling.
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Grand Theft Auto III
Pedestrian and traffic chaos lightly randomises encounters
Grand Theft Auto V
Some mission and lobby randomness.
Grand Theft Auto III leans a little harder on optimization, though the gap is small.
Grand Theft Auto III
Mission routing and city knowledge are learnable systems
Grand Theft Auto V
Heists, money loops, builds learnable.
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.