head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is execution, and it is a single point.

Execution · Practiced Mastery
A twin-stick shooter testing aim and crowd control against zombie hordes.

Execution · Practiced Mastery
Sandbox crime playground spanning shooting, driving, and a persistent online economy.
All Zombies Must Die! leans Execution (Practiced Mastery); Grand Theft Auto V leans Execution (Practiced Mastery).
All Zombies Must Die! leans a little harder on execution, though the gap is small.
All Zombies Must Die!
Twin-stick aiming and dodging hordes is the core skill
Grand Theft Auto V
Driving and shooting demand decent inputs.
Grand Theft Auto V leans a little harder on reads, though the gap is small.
All Zombies Must Die!
Zombies swarm on fixed AI, nothing to out-predict
Grand Theft Auto V
Online PvP exists but mostly gear/positioning, not modeling.
All Zombies Must Die! leans a little harder on variance, though the gap is small.
All Zombies Must Die!
Drops and modifiers add some randomness
Grand Theft Auto V
Some mission and lobby randomness.
All Zombies Must Die! leans a little harder on optimization, though the gap is small.
All Zombies Must Die!
Crafting weapons and quest routing builds power over time
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.