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
The Genesis Castlevania tours war-torn Europe with whip-wielding John Morris and spear-vaulting Eric Lecarde.

Execution · Practiced Mastery
Crowd-control execution against memorised enemy patterns, stage by stage.
Castlevania: Bloodlines leans Execution (Practiced Mastery); Streets of Rage 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.
Castlevania: Bloodlines
Stiff classic movement against demanding Genesis bosses
Streets of Rage
Spacing, crowd control and throw timing carry every stage
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Castlevania: Bloodlines
Scripted monsters throughout
Streets of Rage
Enemy gangs attack from fixed arcade patterns
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Castlevania: Bloodlines
Minor hidden items only
Streets of Rage
Spawns are essentially deterministic per stage
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Castlevania: Bloodlines
Character choice changes paths; patterns are learnable
Streets of Rage
One-credit clears come from learned positioning and patterns
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.