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
The genre-defining metroidvania with deep RPG systems.

Optimization · Pure Optimization
A free-form fantasy RPG where skill-leveling and spell-craft builds dominate.
Castlevania: Symphony of the Night leans Optimization (Pure Optimization); The Elder Scrolls IV: Oblivion leans Optimization (Pure Optimization).
Castlevania: Symphony of the Night leans a little harder on execution, though the gap is small.
Castlevania: Symphony of the Night
Forgiving action combat
The Elder Scrolls IV: Oblivion
Real-time swing and block, modest demand
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
The Elder Scrolls IV: Oblivion
Scripted enemies
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
The Elder Scrolls IV: Oblivion
Loot and level-scaling rolls
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
The Elder Scrolls IV: Oblivion
Skill leveling, spell crafting, exploit-prone builds
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.