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

Optimization · Practiced Mastery
Solving fixed environmental puzzles by trial and error, with light timed stealth.

Optimization · Pure Optimization
A GBA metroidvania built around collecting enemy souls.
Black the Fall leans Optimization (Practiced Mastery); 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.
Black the Fall
Some timed stealth and chase sections demand light precision
Castlevania: Aria of Sorrow
Modest action timing
Castlevania: Aria of Sorrow leans a little harder on reads, though the gap is small.
Black the Fall
Guards and machines run fixed detection scripts
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.
Black the Fall
Puzzle mechanics are unknown until each trial-and-error death
Castlevania: Aria of Sorrow
Soul drops are heavily random
Castlevania: Aria of Sorrow leans a little harder on optimization, though the gap is small.
Black the Fall
Each room is a fixed puzzle with one solution
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.