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

Optimization · Practiced Mastery
Routing scripted patrols with vampire teleports and a light skill-build layer.

Optimization · Practiced Mastery
Action-RPG combat where the panel-grid loadout puzzle matters more than reflexes.
Dark leans Optimization (Practiced Mastery); Kingdom Hearts 358/2 Days leans Optimization (Practiced Mastery).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Dark
Shadow-teleport timing matters but combat is clunky-forgiving
Kingdom Hearts 358/2 Days
Real-time keyblade combat with modest timing demands
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Dark
Guards run scripted patrol and alert routines
Kingdom Hearts 358/2 Days
Heartless and bosses run fixed patterns
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Dark
Patrols are fixed once observed
Kingdom Hearts 358/2 Days
Loot drops add minor randomness to gearing
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Dark
Skill builds and patrol routing solve each stealth arena
Kingdom Hearts 358/2 Days
The panel grid system rewards careful build planning
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.