head to head
Grand Theft Auto: Vice City Stories 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-born GTA prequel adding a business empire system to 1984 Vice City.
Grand Theft Auto V leans Execution (Practiced Mastery); Grand Theft Auto: Vice City Stories leans Optimization (Practiced Mastery).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Grand Theft Auto V
Driving and shooting demand decent inputs.
Grand Theft Auto: Vice City Stories
Driving, aiming, and helicopter handling on a stick
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.
Grand Theft Auto: Vice City Stories
Mission enemies are scripted and predictable
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.
Grand Theft Auto: Vice City Stories
Mostly fixed missions with light traffic randomness
Grand Theft Auto: Vice City Stories leans clearly harder on optimization.
Grand Theft Auto V
Heists, money loops, builds learnable.
Grand Theft Auto: Vice City Stories
Empire-building business system layers economy onto missions
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.