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
Brutal one-hit-death shmup execution over patterns that must be memorised to survive.

Execution · Practiced Mastery
Nintendo's branching rail shooter where score medals demand perfected routes.
Silver Surfer leans Execution (Pure Mechanics); Star Fox 64 leans Execution (Practiced Mastery).
Silver Surfer leans a little harder on execution, though the gap is small.
Silver Surfer
One-hit deaths demand near-perfect dodging every second
Star Fox 64
Rail-shooter aim, barrel rolls, and boost timing are everything
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Silver Surfer
Enemy waves are fully scripted patterns
Star Fox 64
Entirely scripted bosses and waves
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Silver Surfer
Stages replay identically once learned
Star Fox 64
Fully deterministic once routes are known
Star Fox 64 leans a little harder on optimization, though the gap is small.
Silver Surfer
Memorising spawn patterns and safe lines is mandatory study
Star Fox 64
Medal scores and route branches reward total memorization
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.