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
Ezio's Renaissance revenge tale of parkour, assassination, and villa-building across Italy.

Optimization · Practiced Mastery
A lovingly pixelled aerial adventure where Otus carries gunner friends through floating islands.
Assassin's Creed II 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.
Assassin's Creed II
Counter-heavy combat stays forgiving
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.
Assassin's Creed II
Guards follow 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.
Assassin's Creed II
Fixed world and missions
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.
Assassin's Creed II
Villa economy and route planning, lightly
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.