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
A tower-defense hybrid about summoning units and upgrading to survive waves.

Optimization · Pure Optimization
A GBA metroidvania built around collecting enemy souls.
Bardbarian leans Optimization (Pure Optimization); Castlevania: Aria of Sorrow 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.
Bardbarian
Movement dodging matters but isn't the lead
Castlevania: Aria of Sorrow
Modest action timing
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Bardbarian
Enemy waves are scripted, not adaptive
Castlevania: Aria of Sorrow
Scripted enemies
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Bardbarian
Wave composition and drops vary somewhat
Castlevania: Aria of Sorrow
Soul drops are heavily random
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Bardbarian
Summoning units and upgrade choices win waves
Castlevania: Aria of Sorrow
Soul build crafting dominates
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.