head to head
Neither is simply harder - they are hard in different places. Grand Theft Auto V demands more reads; Sparkle Unleashed demands more variance.

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

Execution · Practiced Mastery
A marble-shooter testing aim and color-chain planning against falling orbs.
Grand Theft Auto V leans Execution (Practiced Mastery); Sparkle Unleashed leans Execution (Practiced Mastery).
Sparkle Unleashed leans a little harder on execution, though the gap is small.
Grand Theft Auto V
Driving and shooting demand decent inputs.
Sparkle Unleashed
Aiming and timing orb shots before they fall matters
Grand Theft Auto V leans clearly harder on reads.
Grand Theft Auto V
Online PvP exists but mostly gear/positioning, not modeling.
Sparkle Unleashed
Solo arcade puzzle with no opponent to model
Sparkle Unleashed leans clearly harder on variance.
Grand Theft Auto V
Some mission and lobby randomness.
Sparkle Unleashed
Incoming orb colors arrive with some randomness
Sparkle Unleashed leans clearly harder on optimization.
Grand Theft Auto V
Heists, money loops, builds learnable.
Sparkle Unleashed
Chaining matches and powerup use is the strategic 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.