head to head
Neither is simply harder - they are hard in different places. Bloodstained: Curse of the Moon demands more execution; Grand Theft Auto V demands more reads.

Execution · Practiced Mastery
Deliberate retro platform execution with character-swap route planning.

Execution · Practiced Mastery
Sandbox crime playground spanning shooting, driving, and a persistent online economy.
Bloodstained: Curse of the Moon leans Execution (Practiced Mastery); Grand Theft Auto V leans Execution (Practiced Mastery).
Bloodstained: Curse of the Moon leans clearly harder on execution.
Bloodstained: Curse of the Moon
Stiff retro jumps and boss dodges demand committed inputs
Grand Theft Auto V
Driving and shooting demand decent inputs.
Grand Theft Auto V leans clearly harder on reads.
Bloodstained: Curse of the Moon
Bosses telegraph from strictly fixed scripts
Grand Theft Auto V
Online PvP exists but mostly gear/positioning, not modeling.
Grand Theft Auto V leans a little harder on variance, though the gap is small.
Bloodstained: Curse of the Moon
Levels are deterministic on every run
Grand Theft Auto V
Some mission and lobby randomness.
Bloodstained: Curse of the Moon leans a little harder on optimization, though the gap is small.
Bloodstained: Curse of the Moon
Character-swap routing and branch choices reward planning
Grand Theft Auto V
Heists, money loops, builds learnable.
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.