head to head
Neither is harder. They score identically on all four axes, so the difference between them is in kind, not degree.

Execution · Practiced Mastery
The Genesis Castlevania tours war-torn Europe with whip-wielding John Morris and spear-vaulting Eric Lecarde.

Execution · Practiced Mastery
A 3D platformer where precise movement and camera mastery unlock its many challenges.
Castlevania: Bloodlines leans Execution (Practiced Mastery); Super Mario 64 DS 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.
Castlevania: Bloodlines
Stiff classic movement against demanding Genesis bosses
Super Mario 64 DS
precise 3D platforming and camera control
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Castlevania: Bloodlines
Scripted monsters throughout
Super Mario 64 DS
scripted enemies, no adaptation
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Castlevania: Bloodlines
Minor hidden items only
Super Mario 64 DS
minimal randomness
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Castlevania: Bloodlines
Character choice changes paths; patterns are learnable
Super Mario 64 DS
star routes and speedrun tech 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.