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 · Practiced Mastery
The 3DS remake of Metroid II built around a precisely timed melee counter.

Execution · Practiced Mastery
Movement execution and route optimisation through a fixed, mappable planet.
Metroid: Samus Returns leans Execution (Practiced Mastery); Super Metroid leans Execution (Practiced Mastery).
Super Metroid leans a little harder on execution, though the gap is small.
Metroid: Samus Returns
Melee-counter timing defines nearly every fight.
Super Metroid
Wall-jumps, shinesparks and boss dodges demand precise inputs
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Metroid: Samus Returns
Counters punish scripted lunges, not adaptation.
Super Metroid
Bosses cycle fixed patterns, never adapting
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Metroid: Samus Returns
Fixed map and encounters.
Super Metroid
Item and route knowledge is fixed once discovered
Super Metroid leans a little harder on optimization, though the gap is small.
Metroid: Samus Returns
Aeion management and ability routing matter.
Super Metroid
Sequence-breaking route optimisation is the enduring meta-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.