head to head
Puyo Puyo! 15th Anniversary 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
A competitive falling-blob puzzler about chaining combos faster than your opponent.
Grand Theft Auto: San Andreas leans Optimization (Practiced Mastery); Puyo Puyo! 15th Anniversary leans Execution (Practiced Mastery).
Puyo Puyo! 15th Anniversary leans clearly harder on execution.
Grand Theft Auto: San Andreas
Flying school and drive-bys need decent hands
Puyo Puyo! 15th Anniversary
Fast blob placement under pressure demands quick hands
Puyo Puyo! 15th Anniversary leans clearly harder on reads.
Grand Theft Auto: San Andreas
Gang AI is scripted, never adaptive
Puyo Puyo! 15th Anniversary
Versus play rewards reading opponent chain timing and counters
Puyo Puyo! 15th Anniversary leans clearly harder on variance.
Grand Theft Auto: San Andreas
Territory wars and traffic add light randomness
Puyo Puyo! 15th Anniversary
Next-piece queue is random but bounded and visible
Puyo Puyo! 15th Anniversary 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
Puyo Puyo! 15th Anniversary
Building large chains is a learnable scoring system
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.