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
Rhythm game where clicking circles to the beat becomes an athletic discipline.

Execution · Pure Mechanics
A brutal minimalist platformer where flipping gravity replaces jumping.
osu! leans Execution (Pure Mechanics); VVVVVV leans Execution (Pure Mechanics).
osu! leans a little harder on execution, though the gap is small.
osu!
Pixel-perfect cursor aim and tapping at extreme speeds
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.
osu!
No opponent interaction in scoring
VVVVVV
No opponent
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
osu!
Beatmaps are fully deterministic
VVVVVV
Every hazard is fixed and visible
VVVVVV leans a little harder on optimization, though the gap is small.
osu!
Mod choices and map selection for ranking
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.