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

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

Execution · Practiced Mastery
A co-op horde shooter testing sniper aim and chokepoint planning against scripted waves.
Grand Theft Auto V leans Execution (Practiced Mastery); Zombie Army Trilogy leans Execution (Practiced Mastery).
Zombie Army Trilogy leans a little harder on execution, though the gap is small.
Grand Theft Auto V
Driving and shooting demand decent inputs.
Zombie Army Trilogy
Long-range sniping and horde kiting demand steady aim
Grand Theft Auto V leans clearly harder on reads.
Grand Theft Auto V
Online PvP exists but mostly gear/positioning, not modeling.
Zombie Army Trilogy
Undead waves follow predictable spawn scripts
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.
Zombie Army Trilogy
Spawn timing varies a little between runs
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.
Zombie Army Trilogy
Choke points, trap placement and ammo economy reward planning
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.