head to head
Neither is simply harder - they are hard in different places. Fire Emblem: The Sacred Stones demands more variance; Portal demands more execution.

Optimization · Pure Optimization
Gentler GBA Fire Emblem with branching promotions and an optional grinding tower softening the tactics test.

Optimization · Pure Optimization
The portal-gun puzzle game whose solutions are everything.
Fire Emblem: The Sacred Stones leans Optimization (Pure Optimization); Portal leans Optimization (Pure Optimization).
Portal leans clearly harder on execution.
Fire Emblem: The Sacred Stones
Grid menu tactics; nothing physical.
Portal
Portal placement timing modest.
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Fire Emblem: The Sacred Stones
Enemies use fixed targeting logic.
Portal
No adversary modeling player.
Fire Emblem: The Sacred Stones leans clearly harder on variance.
Fire Emblem: The Sacred Stones
Hit, crit, and growth RNG remain meaningful.
Portal
Deterministic chambers; no randomness.
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Fire Emblem: The Sacred Stones
Branching promotions and grindable maps reward build planning.
Portal
Pure puzzle-solving optimization.
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.