head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is variance, 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
Twitchy cover-shooter rooms that reward drilled execution and memorised routes.
F-Zero X leans Execution (Pure Mechanics); Not a Hero leans Execution (Practiced Mastery).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
F-Zero X
Sixty-frame control of thirty machines at top speed
Not a Hero
Slide-cancels, snap cover and reload timing decide every room
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
F-Zero X
Rival AI is non-adaptive
Not a Hero
Enemies follow fixed behaviours, nothing adapts to you
Not a Hero leans a little harder on variance, though the gap is small.
F-Zero X
X Cup random tracks are a minor mode
Not a Hero
Minor enemy spawn jitter, levels otherwise deterministic
Not a Hero leans a little harder on optimization, though the gap is small.
F-Zero X
Boost-health tradeoffs and shortcuts reward routing
Not a Hero
Learning room layouts and routing kills enables full-clear runs
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.