head to head
Neither is simply harder - they are hard in different places. Super Hexagon demands more execution; Super Mario World demands more optimization.

Execution · Pure Mechanics
Terry Cavanagh's minimalist reflex gauntlet of rotating walls measured in seconds survived.

Execution · Pure Mechanics
Precise jump execution across fixed levels with secrets to memorise.
Super Hexagon leans Execution (Pure Mechanics); Super Mario World leans Execution (Pure Mechanics).
Super Hexagon leans clearly harder on execution.
Super Hexagon
Sub-second reactions at extreme speed, pure reflex ceiling
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.
Super Hexagon
No opponent, only walls
Super Mario World
Scripted Koopas adapt to nothing
Super Hexagon leans a little harder on variance, though the gap is small.
Super Hexagon
Pattern order randomized from a known set
Super Mario World
Levels are fixed; nothing hidden survives one playthrough
Super Mario World leans clearly harder on optimization.
Super Hexagon
Pattern vocabulary is small, reaction is everything
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.