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 · Practiced Mastery
Pattern memorisation and precise platforming with a solvable boss-order route.

Execution · Practiced Mastery
A test of 3D movement control with a deep routing layer underneath.
Mega Man 5 leans Execution (Practiced Mastery); Super Mario 64 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.
Mega Man 5
Precise jumps and buster timing through gauntlet stages
Super Mario 64
Perfect analog inputs trivialise precise jumps, dives and wall-kicks
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Mega Man 5
Robot Masters cycle fixed attack patterns
Super Mario 64
Solo platformer - no adaptive opponent anywhere
Super Mario 64 leans a little harder on variance, though the gap is small.
Mega Man 5
Every stage and boss is identical each attempt
Super Mario 64
Star locations and level layouts are fixed once seen
Mega Man 5 leans a little harder on optimization, though the gap is small.
Mega Man 5
Weapon-order routing and pattern memorisation solve the game
Super Mario 64
Star routing and movement tech form a deep solvable layer
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.