head to head
Super Mario World asks more than Rhythm Heaven Megamix, and the gap is optimization.

Execution · Pure Mechanics
Pure rhythmic timing against fixed musical cues, minigame after minigame.

Execution · Pure Mechanics
Precise jump execution across fixed levels with secrets to memorise.
Rhythm Heaven Megamix leans Execution (Pure Mechanics); Super Mario World leans Execution (Pure Mechanics).
Rhythm Heaven Megamix leans a little harder on execution, though the gap is small.
Rhythm Heaven Megamix
Beat-perfect input timing is the entire test
Super Mario World
Perfect inputs trivialise every jump, spin and cape flight
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Rhythm Heaven Megamix
No opponent - only the music
Super Mario World
Scripted Koopas adapt to nothing
Super Mario World leans a little harder on variance, though the gap is small.
Rhythm Heaven Megamix
Every minigame plays identically each attempt
Super Mario World
Levels are fixed; nothing hidden survives one playthrough
Super Mario World leans clearly harder on optimization.
Rhythm Heaven Megamix
Cues are learned quickly; timing remains the wall
Super Mario World
Secret exits and route knowledge add a modest 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.