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
Haunted-hotel adventure climbing themed floors with vacuum and goo clone.

Optimization · Practiced Mastery
A lovingly pixelled aerial adventure where Otus carries gunner friends through floating islands.
Luigi's Mansion 3 leans Optimization (Practiced Mastery); Owlboy 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.
Luigi's Mansion 3
Slam combos and boss-dodge timing
Owlboy
Flying and gunner-swapping in light combat
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Luigi's Mansion 3
Floor bosses run fixed scripts
Owlboy
Scripted pirates and bosses
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Luigi's Mansion 3
Hotel floors are authored
Owlboy
Hand-crafted, deterministic world
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Luigi's Mansion 3
Gooigi puzzles and gem routes are solvable
Owlboy
Boss patterns and secrets are learnable
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.