head to head
Grand Theft Auto V asks more than Alien Breed 2: Assault, and the gap is reads.

Execution · Practiced Mastery
Kiting and shooting scripted alien swarms with modest resource management underneath.

Execution · Practiced Mastery
Sandbox crime playground spanning shooting, driving, and a persistent online economy.
Alien Breed 2: Assault leans Execution (Practiced Mastery); Grand Theft Auto V leans Execution (Practiced Mastery).
Alien Breed 2: Assault leans a little harder on execution, though the gap is small.
Alien Breed 2: Assault
Twin-stick aim and kiting under swarm pressure decide survival
Grand Theft Auto V
Driving and shooting demand decent inputs.
Grand Theft Auto V leans clearly harder on reads.
Alien Breed 2: Assault
Alien hordes path predictably with no adaptation
Grand Theft Auto V
Online PvP exists but mostly gear/positioning, not modeling.
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Alien Breed 2: Assault
Ambush placements are scripted-but-unknown on first run
Grand Theft Auto V
Some mission and lobby randomness.
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Alien Breed 2: Assault
Ammo economy and route knowledge smooth repeat playthroughs
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.