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
Mission-based sequel sending Luigi through five haunted mansions with the Poltergust.
Assassin's Creed II leans Optimization (Practiced Mastery); Luigi's Mansion: Dark Moon 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
Luigi's Mansion: Dark Moon
Strobe timing and vacuum wrangling
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
Luigi's Mansion: Dark Moon
Ghosts are scripted mischief, not adaptive
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
Luigi's Mansion: Dark Moon
Mission layouts are fixed
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
Luigi's Mansion: Dark Moon
Gem hunting and mission rank routing
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.