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

Execution · Pure Mechanics
The Nokia classic testing steering discipline as the snake fills the screen.

Execution · Pure Mechanics
Precise jump execution across fixed levels with secrets to memorise.
Snake II leans Execution (Pure Mechanics); Super Mario World leans Execution (Pure Mechanics).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Snake II
Keypad steering an ever-longer snake is pure motor discipline
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.
Snake II
Solo - nothing opposes you
Super Mario World
Scripted Koopas adapt to nothing
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Snake II
Food spawns are random but trivially handled
Super Mario World
Levels are fixed; nothing hidden survives one playthrough
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Snake II
Space-filling path patterns are known and learnable
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.