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 run-and-gun boss rush about dodging scripted patterns with tight inputs.

Execution · Practiced Mastery
A classic frenetic shooter that rewards fast reflexes and mastering enemy patterns.
Cuphead leans Execution (Pure Mechanics); The Ultimate Doom leans Execution (Practiced Mastery).
Cuphead leans a little harder on execution, though the gap is small.
Cuphead
Tight dodging and parry timing decide every boss.
The Ultimate Doom
twitch aim and movement drive combat
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.
The Ultimate Doom
fixed demon patterns, no adaptation
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Cuphead
Minor attack-order shuffling between phases.
The Ultimate Doom
minor spawn and drop randomness
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Cuphead
Loadouts and boss phase order are fully learnable.
The Ultimate Doom
weapon routing and glory-kill loops solvable
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.