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
NES platformer that codified boss-weakness ordering and tight jump-and-shoot play.
Mega Man leans Execution (Practiced Mastery); Mega Man 2 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
Mega Man 2
precise jumps and boss dodges under pressure
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
Mega Man 2
robot masters follow strict patterns
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
Mega Man 2
deterministic once stage layouts known
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
Mega Man 2
weapon-weakness ordering is the classic solve
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.