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

Optimization · Pure Optimization
The genre-defining metroidvania with deep RPG systems.

Optimization · Pure Optimization
A hybrid real-time and tactical action RPG in a digital city.
Castlevania: Symphony of the Night leans Optimization (Pure Optimization); Transistor leans Optimization (Pure Optimization).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Castlevania: Symphony of the Night
Forgiving action combat
Transistor
Real-time and planned hybrid combat.
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Castlevania: Symphony of the Night
Scripted bosses
Transistor
Process enemies follow scripts.
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Castlevania: Symphony of the Night
Item drops and rare gear
Transistor
Limited randomness.
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Castlevania: Symphony of the Night
Build crafting and sequence breaks
Transistor
Function loadouts have deep optimization.
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.