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.

Optimization · Practiced Mastery
The 1986 original that defined exploration-driven, secret-riddled platforming.

Execution · Practiced Mastery
Tense, linear Metroid hunted through a station by a clone of yourself.
Metroid leans Optimization (Practiced Mastery); Metroid Fusion leans Execution (Practiced Mastery).
Metroid Fusion leans a little harder on execution, though the gap is small.
Metroid
stiff NES jumps and tough enemy contact
Metroid Fusion
demanding bosses for a 2D Metroid
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Metroid
creatures follow fixed movement
Metroid Fusion
SA-X stalking runs on fixed scripts
Metroid leans a little harder on variance, though the gap is small.
Metroid
unmarked secrets and bombable blocks hide the map
Metroid Fusion
first-encounter dread fades once mapped
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Metroid
route and item knowledge transforms the game
Metroid Fusion
guided structure still rewards route and pattern knowledge
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.