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.

Execution · Pure Mechanics
Faster, gorier sequel built around dismembering aggressive enemies before they swarm you.

Execution · Practiced Mastery
A character action RPG built on tight parry timing against elaborate scripted bosses.
Ninja Gaiden Sigma 2 leans Execution (Pure Mechanics); Stellar Blade leans Execution (Practiced Mastery).
Ninja Gaiden Sigma 2 leans a little harder on execution, though the gap is small.
Ninja Gaiden Sigma 2
Delimb-and-finish combat under constant projectile pressure stays brutal
Stellar Blade
Parry and perfect-dodge timing windows define the ceiling
Stellar Blade leans a little harder on reads, though the gap is small.
Ninja Gaiden Sigma 2
Aggressive enemy AI remains pattern-driven
Stellar Blade
Bosses run fixed movesets, learnable not adaptive
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Ninja Gaiden Sigma 2
Fixed missions; little randomness across runs
Stellar Blade
Encounters and loot are static and predictable
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Ninja Gaiden Sigma 2
Weapon matchups and essence routing reward system study
Stellar Blade
Exospine builds, gear and moveset study reward preparation
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.