head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is execution, and it is a single point.

Optimization · Pure Optimization
A speedy GBA metroidvania that doubles its castle into two mirrored layouts to untangle.

Optimization · Practiced Mastery
An action RPG where leveling means choosing which Londoners to drain.
Castlevania: Harmony of Dissonance leans Optimization (Pure Optimization); Vampyr leans Optimization (Practiced Mastery).
Vampyr leans a little harder on execution, though the gap is small.
Castlevania: Harmony of Dissonance
Fast dashes make combat forgiving.
Vampyr
Dodge-and-stamina melee combat with modest demands
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Castlevania: Harmony of Dissonance
Scripted enemies and bosses.
Vampyr
Enemies follow scripted patterns
Vampyr leans a little harder on variance, though the gap is small.
Castlevania: Harmony of Dissonance
Minor relic and drop luck.
Vampyr
Citizen secrets are hidden until investigated
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Castlevania: Harmony of Dissonance
Twin-castle navigation and spellbook combos carry it.
Vampyr
The feed-or-spare XP economy is the central solvable system
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.