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 · Pure Optimization
A lemmings-style puzzle series testing deterministic route planning for marching minis.
Castlevania: Harmony of Dissonance leans Optimization (Pure Optimization); Mario vs. Donkey Kong: Tipping Stars leans Optimization (Pure Optimization).
Castlevania: Harmony of Dissonance leans a little harder on execution, though the gap is small.
Castlevania: Harmony of Dissonance
Fast dashes make combat forgiving.
Mario vs. Donkey Kong: Tipping Stars
Stylus rib-placement under mild time pressure
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.
Mario vs. Donkey Kong: Tipping Stars
Minis follow strict lemming-like movement rules
Castlevania: Harmony of Dissonance leans a little harder on variance, though the gap is small.
Castlevania: Harmony of Dissonance
Minor relic and drop luck.
Mario vs. Donkey Kong: Tipping Stars
Puzzles are fully deterministic and visible
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.
Mario vs. Donkey Kong: Tipping Stars
Routing minis to the door efficiently is the whole test
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.
full breakdown
Castlevania: Harmony of Dissonance →
full breakdown
Mario vs. Donkey Kong: Tipping Stars →