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

Execution · Pure Mechanics
A run-and-gun boss rush about dodging scripted patterns with tight inputs.

Execution · Practiced Mastery
Pure time-trial racing testing relentless execution of an ever-more-optimised line.
Cuphead leans Execution (Pure Mechanics); TrackMania United Forever leans Execution (Practiced Mastery).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Cuphead
Tight dodging and parry timing decide every boss.
TrackMania United Forever
Frame-perfect lines over hundreds of restarts are everything
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Cuphead
Bosses cycle scripted phases; no adaptation to player.
TrackMania United Forever
Time trials against ghosts - no one adapts to you
Cuphead leans a little harder on variance, though the gap is small.
Cuphead
Minor attack-order shuffling between phases.
TrackMania United Forever
Deterministic physics with literally nothing hidden
TrackMania United Forever leans a little harder on optimization, though the gap is small.
Cuphead
Loadouts and boss phase order are fully learnable.
TrackMania United Forever
Finding the theoretical fastest line is the meta-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.