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
Twin assassins seize Victorian London borough by borough with gang warfare and a rope launcher.

Optimization · Practiced Mastery
Working through scripted movie levels where route knowledge outweighs reflexes.
Assassin's Creed Syndicate leans Optimization (Practiced Mastery); Star Wars Episode I: The Phantom Menace 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 Syndicate
Rope-launcher traversal and simple brawling
Star Wars Episode I: The Phantom Menace
Clunky saber combat and platforming ask modest precision
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Assassin's Creed Syndicate
Gangs are scripted
Star Wars Episode I: The Phantom Menace
Enemies follow simple fixed scripts
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Assassin's Creed Syndicate
Fixed activities
Star Wars Episode I: The Phantom Menace
Level layouts are fixed and quickly learned
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Assassin's Creed Syndicate
Gang upgrades and borough takeover planning
Star Wars Episode I: The Phantom Menace
Knowing dialogue paths and level routes carries the game
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.