head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is reads, and it is a single point.

Optimization · Practiced Mastery
Action-RPG combat where the panel-grid loadout puzzle matters more than reflexes.

Optimization · Pure Optimization
A scripted RPG where pattern-learning and pacifist routing carry you.
Kingdom Hearts 358/2 Days leans Optimization (Practiced Mastery); Undertale 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.
Kingdom Hearts 358/2 Days
Real-time keyblade combat with modest timing demands
Undertale
Bullet-hell dodging in scripted patterns
Undertale leans a little harder on reads, though the gap is small.
Kingdom Hearts 358/2 Days
Heartless and bosses run fixed patterns
Undertale
NPCs follow fixed dialogue trees, not adaptive
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Kingdom Hearts 358/2 Days
Loot drops add minor randomness to gearing
Undertale
Minimal randomness in encounters
Undertale leans a little harder on optimization, though the gap is small.
Kingdom Hearts 358/2 Days
The panel grid system rewards careful build planning
Undertale
Learning fixed boss patterns and mercy routes wins
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.