head to head
Neither is simply harder - they are hard in different places. Grand Theft Auto V demands more reads; Tales of Symphonia demands more optimization.

Execution · Practiced Mastery
Sandbox crime playground spanning shooting, driving, and a persistent online economy.

Execution · Practiced Mastery
A real-time action JRPG where mastering guard cancels and arte combos against scripted enemies defines high-level play.
Grand Theft Auto V leans Execution (Practiced Mastery); Tales of Symphonia leans Execution (Practiced Mastery).
Tales of Symphonia leans clearly harder on execution.
Grand Theft Auto V
Driving and shooting demand decent inputs.
Tales of Symphonia
3D combat movement, guard-canceling, and combo timing are central skills
Grand Theft Auto V leans clearly harder on reads.
Grand Theft Auto V
Online PvP exists but mostly gear/positioning, not modeling.
Tales of Symphonia
All enemy and boss patterns are scripted
Tales of Symphonia leans a little harder on variance, though the gap is small.
Grand Theft Auto V
Some mission and lobby randomness.
Tales of Symphonia
Random item drops and some enemy move randomness present
Tales of Symphonia leans clearly harder on optimization.
Grand Theft Auto V
Heists, money loops, builds learnable.
Tales of Symphonia
Arte trees, Unison Attacks, and equipment crafting are the optimization layer
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.