head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is reads, and it is a single point.

Execution · Pure Mechanics
An arcade test of jump timing and enemy-flipping precision on a single screen.

Execution · Pure Mechanics
An endless arcade runner testing reflexes against scrolling hazards.
Mario Bros. leans Execution (Pure Mechanics); Nyan Cat: Lost In Space 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.
Mario Bros.
Precise jumps and bump timing under crowding enemies decide survival
Nyan Cat: Lost In Space
Precise dodging and platform timing decides survival
Mario Bros. leans a little harder on reads, though the gap is small.
Mario Bros.
Versus mode adds light human interference, enemies are scripted
Nyan Cat: Lost In Space
No opponent to predict; scripted hazards
Nyan Cat: Lost In Space leans a little harder on variance, though the gap is small.
Mario Bros.
Enemy spawns vary slightly but patterns are quickly learned
Nyan Cat: Lost In Space
Procedural obstacle layouts add some unpredictability
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Mario Bros.
POW block usage and enemy routing have known best lines
Nyan Cat: Lost In Space
Upgrade choices and route knowledge improve runs
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.