head to head
Neither is harder. They score identically on all four axes, so the difference between them is in kind, not degree.

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

Execution · Practiced Mastery
The Genesis Castlevania tours war-torn Europe with whip-wielding John Morris and spear-vaulting Eric Lecarde.
Bloodstained: Curse of the Moon leans Execution (Practiced Mastery); Castlevania: Bloodlines leans Execution (Practiced Mastery).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Bloodstained: Curse of the Moon
Stiff retro jumps and boss dodges demand committed inputs
Castlevania: Bloodlines
Stiff classic movement against demanding Genesis bosses
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Bloodstained: Curse of the Moon
Bosses telegraph from strictly fixed scripts
Castlevania: Bloodlines
Scripted monsters throughout
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Bloodstained: Curse of the Moon
Levels are deterministic on every run
Castlevania: Bloodlines
Minor hidden items only
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Bloodstained: Curse of the Moon
Character-swap routing and branch choices reward planning
Castlevania: Bloodlines
Character choice changes paths; patterns are 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.