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

Execution · Pure Mechanics
Treasure's Mega Drive boss-rush gauntlet demanding flawless execution against giant setpieces.

Execution · Practiced Mastery
NES platformer that codified boss-weakness ordering and tight jump-and-shoot play.
Alien Soldier leans Execution (Pure Mechanics); Mega Man 2 leans Execution (Practiced Mastery).
Alien Soldier leans a little harder on execution, though the gap is small.
Alien Soldier
Frame-tight dodges across thirty-plus bosses
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.
Alien Soldier
Bosses fully scripted
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.
Alien Soldier
Nothing hidden after one loop
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.
Alien Soldier
Weapon loadout and moveset mastery solvable
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.