head to head
Serious Sam: The Second Encounter asks more than Grand Theft Auto: San Andreas, and the gap is execution.

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

Execution · Practiced Mastery
An over-the-top horde shooter throwing hundreds of charging enemies at you.
Grand Theft Auto: San Andreas leans Optimization (Practiced Mastery); Serious Sam: The Second Encounter leans Execution (Practiced Mastery).
Serious Sam: The Second Encounter leans clearly harder on execution.
Grand Theft Auto: San Andreas
Flying school and drive-bys need decent hands
Serious Sam: The Second Encounter
Circle-strafing huge horde waves tests stamina and aim
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Grand Theft Auto: San Andreas
Gang AI is scripted, never adaptive
Serious Sam: The Second Encounter
Enemies charge in fixed patterns
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
Serious Sam: The Second Encounter
Wave compositions memorised after one run
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Grand Theft Auto: San Andreas
Stats, gym, weapon skill, and routes reward systematic play
Serious Sam: The Second Encounter
Prioritising targets and managing arenas is 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.