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.

Execution · Pure Mechanics
A classic 2D Mario platformer rewarding tight jump execution above all.

Execution · Pure Mechanics
A brutal minimalist platformer where flipping gravity replaces jumping.
New Super Mario Bros. U Deluxe leans Execution (Pure Mechanics); VVVVVV leans Execution (Pure Mechanics).
VVVVVV leans a little harder on execution, though the gap is small.
New Super Mario Bros. U Deluxe
precise jump and platforming execution
VVVVVV
Pixel-perfect gravity flips through spike gauntlets
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
New Super Mario Bros. U Deluxe
fixed enemy patterns, no adaptation
VVVVVV
No opponent
New Super Mario Bros. U Deluxe leans a little harder on variance, though the gap is small.
New Super Mario Bros. U Deluxe
minor enemy placement randomness
VVVVVV
Every hazard is fixed and visible
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
New Super Mario Bros. U Deluxe
level routing for speed/collectibles
VVVVVV
Routes are short and obvious; execution is everything
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.