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
Old-school platforming execution through short, fixed western levels.

Execution · Practiced Mastery
Simon Belmont's SNES remake-quest with a multidirectional whip and a moody trek to Dracula.
Gunman Clive leans Execution (Pure Mechanics); Super Castlevania IV 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.
Gunman Clive
Tight jumps and duck-shoot timing carry all sixteen levels
Super Castlevania IV
Eight-way whip control and stair commitment test precision
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Gunman Clive
Bandits and bosses run fixed patterns
Super Castlevania IV
Classic scripted monster patterns
Super Castlevania IV leans a little harder on variance, though the gap is small.
Gunman Clive
Levels never change between attempts
Super Castlevania IV
Hidden wall meat, fixed locations
Super Castlevania IV leans a little harder on optimization, though the gap is small.
Gunman Clive
Boss pattern learning and weapon upgrades round out clears
Super Castlevania IV
Subweapon choice and boss pattern study
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.