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
Memorising punishing fixed stages and executing precise run-and-gun inputs.

Execution · Pure Mechanics
Pure jump timing over fully fixed, memorisable levels.
Journey to Silius leans Execution (Pure Mechanics); Super Mario Bros. 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.
Journey to Silius
Precise jumps and dodges under NES-hard pressure define it
Super Mario Bros.
Perfect inputs trivialise momentum jumps over fixed hazards
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Journey to Silius
Every enemy and boss is rigidly scripted
Super Mario Bros.
Goombas walk left forever - nothing to predict
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Journey to Silius
Identical layouts and spawns every attempt
Super Mario Bros.
Every level is identical on every run
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Journey to Silius
Weapon-energy budgeting and pattern memorisation make clears possible
Super Mario Bros.
Level memorisation and warp routing are fully solvable
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.