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 cinematic action adventure retelling Journey to the West in a post-apocalypse.
Assassin's Creed II leans Optimization (Practiced Mastery); Enslaved: Odyssey to the West 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
Enslaved: Odyssey to the West
Forgiving combat and automated climbing
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
Enslaved: Odyssey to the West
Mechs are scripted
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
Enslaved: Odyssey to the West
Encounters fully 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
Enslaved: Odyssey to the West
Upgrades and encounter solutions 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.