head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is execution, and it is a single point.

Optimization · Pure Optimization
Open-city LEGO cop comedy stuffed with disguise-gated collectibles.

Optimization · Pure Optimization
Sequel that adds a mother-daughter pair to its impossible-architecture puzzles.
LEGO City Undercover leans Optimization (Pure Optimization); Monument Valley 2 leans Optimization (Pure Optimization).
LEGO City Undercover leans a little harder on execution, though the gap is small.
LEGO City Undercover
Easygoing chases, brawls, and platforming
Monument Valley 2
Gentle touch controls, no reflexes
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
LEGO City Undercover
Scripted crooks
Monument Valley 2
Nothing opposes you
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
LEGO City Undercover
Open city fixed once explored
Monument Valley 2
Deterministic authored levels
Monument Valley 2 leans a little harder on optimization, though the gap is small.
LEGO City Undercover
Disguise-ability gating across a collectible-stuffed city
Monument Valley 2
Geometry manipulation puzzles with intended solutions
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.