head to head
Worms Forts: Under Siege asks more than Grand Theft Auto: San Andreas, and the gap is reads.

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

Execution · Practiced Mastery
Artillery aim under wind combined with fort economy planning against human opponents.
Grand Theft Auto: San Andreas leans Optimization (Practiced Mastery); Worms Forts: Under Siege leans Execution (Practiced Mastery).
Worms Forts: Under Siege leans clearly harder on execution.
Grand Theft Auto: San Andreas
Flying school and drive-bys need decent hands
Worms Forts: Under Siege
Manual trajectory aiming under wind decides each shot
Worms Forts: Under Siege leans clearly harder on reads.
Grand Theft Auto: San Andreas
Gang AI is scripted, never adaptive
Worms Forts: Under Siege
Human opponents to outguess on building and target priorities
Worms Forts: Under Siege leans a little harder on variance, though the gap is small.
Grand Theft Auto: San Andreas
Territory wars and traffic add light randomness
Worms Forts: Under Siege
Wind, crates and terrain damage randomize turns
Grand Theft Auto: San Andreas 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
Worms Forts: Under Siege
Fort placement and weapon-tech economy reward planning
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.