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
Precise jump execution across fixed levels with secrets to memorise.

Execution · Pure Mechanics
A ball-rolling balance game testing precise tilt control through stages.
Super Mario World leans Execution (Pure Mechanics); Super Monkey Ball: Step & Roll leans Execution (Pure Mechanics).
Super Monkey Ball: Step & Roll leans a little harder on execution, though the gap is small.
Super Mario World
Perfect inputs trivialise every jump, spin and cape flight
Super Monkey Ball: Step & Roll
Precise tilt-balance control through obstacle courses is decisive
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Super Mario World
Scripted Koopas adapt to nothing
Super Monkey Ball: Step & Roll
Solo with no adaptive opponent
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Super Mario World
Levels are fixed; nothing hidden survives one playthrough
Super Monkey Ball: Step & Roll
Stages are fixed and deterministic
Super Monkey Ball: Step & Roll leans a little harder on optimization, though the gap is small.
Super Mario World
Secret exits and route knowledge add a modest solvable layer
Super Monkey Ball: Step & Roll
Finding optimal lines and shortcuts improves times
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.