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
A boss-rush action game that is nothing but execution tests against scripted duelists.

Execution · Pure Mechanics
Course-corrected revision restoring difficulty to the trilogy's weakest entry.
Furi leans Execution (Pure Mechanics); Ninja Gaiden 3: Razor's Edge leans Execution (Pure Mechanics).
Furi leans a little harder on execution, though the gap is small.
Furi
Parry timing, bullet dodging, and duel precision
Ninja Gaiden 3: Razor's Edge
Steel-on-bone counters still demand sharp hands
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Furi
Bosses are scripted patterns, however adversarial they feel
Ninja Gaiden 3: Razor's Edge
Scripted enemy waves
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Furi
Fixed boss sequences
Ninja Gaiden 3: Razor's Edge
Deterministic encounters
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Furi
Learning each boss's phases converges to mastery
Ninja Gaiden 3: Razor's Edge
Simplified systems leave less to solve
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.