head to head
Neither is simply harder - they are hard in different places. Grand Theft Auto V demands more reads; Super Mario World 2: Yoshi's Island demands more optimization.

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

Execution · Practiced Mastery
A pastel platformer where Yoshi carries Baby Mario and perfect scores demand finding everything.
Grand Theft Auto V leans Execution (Practiced Mastery); Super Mario World 2: Yoshi's Island leans Execution (Practiced Mastery).
Super Mario World 2: Yoshi's Island leans a little harder on execution, though the gap is small.
Grand Theft Auto V
Driving and shooting demand decent inputs.
Super Mario World 2: Yoshi's Island
Egg-aiming and flutter jumps for 100 percent scores
Grand Theft Auto V leans clearly harder on reads.
Grand Theft Auto V
Online PvP exists but mostly gear/positioning, not modeling.
Super Mario World 2: Yoshi's Island
All enemies are scripted
Grand Theft Auto V leans a little harder on variance, though the gap is small.
Grand Theft Auto V
Some mission and lobby randomness.
Super Mario World 2: Yoshi's Island
Collectibles hidden only until found
Super Mario World 2: Yoshi's Island leans clearly harder on optimization.
Grand Theft Auto V
Heists, money loops, builds learnable.
Super Mario World 2: Yoshi's Island
Perfect-score runs demand full collectible routing
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.