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 dual-protagonist western shooter testing aim and learned stealth routes through scripted levels.

Execution · Practiced Mastery
Sandbox crime playground spanning shooting, driving, and a persistent online economy.
Call of Juarez leans Execution (Practiced Mastery); Grand Theft Auto V leans Execution (Practiced Mastery).
Call of Juarez leans a little harder on execution, though the gap is small.
Call of Juarez
Gunplay and whip platforming need steady aim and timing
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.
Call of Juarez
Campaign enemies are scripted; multiplayer is an afterthought
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.
Call of Juarez
Stealth patrols are unknown first time through, then fixed
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.
Call of Juarez
Learning each chapter's intended approach for both characters
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.