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
Arcade shmup reflexes welded to frame-perfect stage memorisation.

Execution · Practiced Mastery
Movement execution and route optimisation through a fixed, mappable planet.
Salamander leans Execution (Practiced Mastery); Super Metroid leans Execution (Practiced Mastery).
Salamander leans a little harder on execution, though the gap is small.
Salamander
Bullet weaving and terrain dodging at arcade pace
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.
Salamander
Enemy waves are scripted to the frame
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.
Salamander
Identical attract-mode determinism every credit
Super Metroid
Item and route knowledge is fixed once discovered
Super Metroid leans a little harder on optimization, though the gap is small.
Salamander
Memorising stage layouts and power-up routes is survival
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.