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

Execution · Practiced Mastery
An action RPG where narrative depth is paired with moderately solvable combat systems.

Optimization · Practiced Mastery
Routing guard patrols and executing clean stealth kills through fixed missions.
NieR leans Execution (Practiced Mastery); Tenchu Z leans Optimization (Practiced Mastery).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
NieR
combat timing and dodges matter
Tenchu Z
Stealth-kill timing and movement control matter but forgive
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
NieR
scripted enemies, no adaptation
Tenchu Z
Guard patrols are scripted, mappable routes
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
NieR
loot and encounter randomness
Tenchu Z
Patrol routes are unknown only on first attempts
Tenchu Z leans a little harder on optimization, though the gap is small.
NieR
builds and side systems solvable
Tenchu Z
Routing each mission for undetected kills is the real game
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.