head to head
Zombie Army 4: Dead War 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 co-op horde shooter about sniping waves of occult Nazi undead.
Grand Theft Auto: San Andreas leans Optimization (Practiced Mastery); Zombie Army 4: Dead War leans Execution (Practiced Mastery).
Zombie Army 4: Dead War leans clearly harder on execution.
Grand Theft Auto: San Andreas
Flying school and drive-bys need decent hands
Zombie Army 4: Dead War
Long-range headshots and horde crowd control
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 Army 4: Dead War
Undead waves never adapt
Zombie Army 4: Dead War leans a little harder on variance, though the gap is small.
Grand Theft Auto: San Andreas
Territory wars and traffic add light randomness
Zombie Army 4: Dead War
Spawn variation and elite placement shuffle runs
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 Army 4: Dead War
Loadout perks, trap placement, score-chain 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.