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

Execution · Pure Mechanics
A run-and-gun boss rush about dodging scripted patterns with tight inputs.

Execution · Pure Mechanics
One of the most mechanically demanding racers ever made, where mastering its physics tech is everything.
Cuphead leans Execution (Pure Mechanics); F-Zero GX leans Execution (Pure Mechanics).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Cuphead
Tight dodging and parry timing decide every boss.
F-Zero GX
Snaking and frame-tight control at absurd speeds
F-Zero GX leans a little harder on reads, though the gap is small.
Cuphead
Bosses cycle scripted phases; no adaptation to player.
F-Zero GX
No adaptive opposition
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Cuphead
Minor attack-order shuffling between phases.
F-Zero GX
Fixed tracks, deterministic physics
Cuphead leans a little harder on optimization, though the gap is small.
Cuphead
Loadouts and boss phase order are fully learnable.
F-Zero GX
Machine settings and advanced technique routes are mappable
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.