head to head
Zombie Shooter 2 asks more than Grand Theft Auto: San Andreas, and the gap is execution.

Optimization · Practiced Mastery
A sprawling open-world crime epic with RPG-style character stats across a whole state.

Execution · Practiced Mastery
A top-down shooter about mowing through zombie hordes with upgradable weapons.
Grand Theft Auto: San Andreas leans Optimization (Practiced Mastery); Zombie Shooter 2 leans Execution (Practiced Mastery).
Zombie Shooter 2 leans clearly harder on execution.
Grand Theft Auto: San Andreas
Flying school and drive-bys need decent hands
Zombie Shooter 2
twin-stick aim against zombie hordes
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Grand Theft Auto: San Andreas
Gang AI is scripted, never adaptive
Zombie Shooter 2
scripted zombie waves, no adaptation
Zombie Shooter 2 leans a little harder on variance, though the gap is small.
Grand Theft Auto: San Andreas
Territory wars and traffic add light randomness
Zombie Shooter 2
loot drops and spawn randomness
Grand Theft Auto: San Andreas leans a little harder on optimization, though the gap is small.
Grand Theft Auto: San Andreas
Stats, gym, weapon skill, and routes reward systematic play
Zombie Shooter 2
weapon upgrade and build optimization
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.