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

Execution · Practiced Mastery
A grittier crime story where weighty driving and gunplay carry the experience.

Execution · Practiced Mastery
An open-world crime game where combat combos and driving skill carry the action.
Grand Theft Auto IV leans Execution (Practiced Mastery); Sleeping Dogs leans Execution (Practiced Mastery).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Grand Theft Auto IV
Heavier driving and cover shooting reward control.
Sleeping Dogs
brawling and driving need timing/aim
Grand Theft Auto IV leans a little harder on reads, though the gap is small.
Grand Theft Auto IV
Scripted AI, no adaptive opponent modeling.
Sleeping Dogs
scripted enemy AI, no adaptation
Grand Theft Auto IV leans a little harder on variance, though the gap is small.
Grand Theft Auto IV
Minor mission variance.
Sleeping Dogs
minor loot and traffic randomness
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Grand Theft Auto IV
Mission routing and weapon picks learnable.
Sleeping Dogs
upgrade paths and mission routes solvable
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.