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

Execution · Practiced Mastery
Demanding platform execution plus a solvable boss-weakness ordering puzzle.

Execution · Practiced Mastery
Arcade shmup reflexes welded to frame-perfect stage memorisation.
Mega Man leans Execution (Practiced Mastery); Salamander leans Execution (Practiced Mastery).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Mega Man
Pixel-precise jumps and shots against brutal fixed stages
Salamander
Bullet weaving and terrain dodging at arcade pace
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Mega Man
Robot Masters cycle rigid scripted patterns
Salamander
Enemy waves are scripted to the frame
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Mega Man
Nothing changes between attempts
Salamander
Identical attract-mode determinism every credit
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Mega Man
Boss-order weakness routing is a known solvable layer
Salamander
Memorising stage layouts and power-up routes is survival
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.