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
The N64 entry whose boost-or-survive health gamble layers routing decisions onto raw speed control.

Execution · Practiced Mastery
Flight school score-attack where smooth control of quirky aircraft earns medals.
F-Zero X leans Execution (Pure Mechanics); Pilotwings 64 leans Execution (Practiced Mastery).
F-Zero X leans a little harder on execution, though the gap is small.
F-Zero X
Sixty-frame control of thirty machines at top speed
Pilotwings 64
Precise stick control of gyrocopter and jetpack
F-Zero X leans a little harder on reads, though the gap is small.
F-Zero X
Rival AI is non-adaptive
Pilotwings 64
No opposition, only score targets
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
F-Zero X
X Cup random tracks are a minor mode
Pilotwings 64
Courses fully fixed
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
F-Zero X
Boost-health tradeoffs and shortcuts reward routing
Pilotwings 64
Optimal lines and landings reward study
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.