head to head
Neither is simply harder - they are hard in different places. Grand Theft Auto V demands more reads; Lumines Electronic Symphony demands more execution.

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

Execution · Practiced Mastery
Sustained block-placement speed synced to a sweeping musical timeline.
Grand Theft Auto V leans Execution (Practiced Mastery); Lumines Electronic Symphony leans Execution (Practiced Mastery).
Lumines Electronic Symphony leans clearly harder on execution.
Grand Theft Auto V
Driving and shooting demand decent inputs.
Lumines Electronic Symphony
Placing blocks against the timeline sweep demands sustained speed
Grand Theft Auto V leans clearly harder on reads.
Grand Theft Auto V
Online PvP exists but mostly gear/positioning, not modeling.
Lumines Electronic Symphony
Solo - no opponent to predict
Lumines Electronic Symphony leans a little harder on variance, though the gap is small.
Grand Theft Auto V
Some mission and lobby randomness.
Lumines Electronic Symphony
Random block sequences shape each run moderately
Lumines Electronic Symphony leans a little harder on optimization, though the gap is small.
Grand Theft Auto V
Heists, money loops, builds learnable.
Lumines Electronic Symphony
Square-chaining setups and skin-speed strategy reward study
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.