head to head
Neither is harder. They score identically on all four axes, so the difference between them is in kind, not degree.

Optimization · Pure Optimization
Remake of Gaiden with dual protagonists and explorable dungeons.

Optimization · Pure Optimization
Methodically mapping a fixed labyrinth while managing levelling and gear economy.
Fire Emblem Echoes: Shadows of Valentia leans Optimization (Pure Optimization); Shining in the Darkness leans Optimization (Pure Optimization).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Fire Emblem Echoes: Shadows of Valentia
Turn-based menus only
Shining in the Darkness
Menu-driven turn battles need no dexterity
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Fire Emblem Echoes: Shadows of Valentia
Scripted enemies on both routes
Shining in the Darkness
Monsters follow fixed behaviour tables
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Fire Emblem Echoes: Shadows of Valentia
Hit RNG plus dungeon encounters
Shining in the Darkness
Maze layout and random encounters are unknown until mapped
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Fire Emblem Echoes: Shadows of Valentia
Dual-army routing and class promotions
Shining in the Darkness
Mapping the labyrinth and grinding gear efficiently is the 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.