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.

Optimization · Practiced Mastery
A sprawling open-world crime epic with RPG-style character stats across a whole state.

Optimization · Practiced Mastery
Stealth systems mastery against scripted guards with moderate execution needs.
Grand Theft Auto: San Andreas leans Optimization (Practiced Mastery); Metal Gear Solid 3: Subsistence leans Optimization (Practiced Mastery).
Metal Gear Solid 3: Subsistence leans a little harder on execution, though the gap is small.
Grand Theft Auto: San Andreas
Flying school and drive-bys need decent hands
Metal Gear Solid 3: Subsistence
CQC, aiming and timed escapes demand real but moderate precision
Metal Gear Solid 3: Subsistence leans a little harder on reads, though the gap is small.
Grand Theft Auto: San Andreas
Gang AI is scripted, never adaptive
Metal Gear Solid 3: Subsistence
Guards and bosses run rich but ultimately scripted behaviours
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Grand Theft Auto: San Andreas
Territory wars and traffic add light randomness
Metal Gear Solid 3: Subsistence
Patrols and boss quirks are unknown only until studied
Metal Gear Solid 3: Subsistence leans a little harder on optimization, though the gap is small.
Grand Theft Auto: San Andreas
Stats, gym, weapon skill, and routes reward systematic play
Metal Gear Solid 3: Subsistence
Camo, food and route systems reward deep mastery
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.