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
Zero awakens to lead a resistance in a harsh, rank-graded GBA action series debut.

Execution · Practiced Mastery
A 3D platformer about precise gravity-bending jumps through fixed galaxies.
Mega Man Zero leans Execution (Practiced Mastery); Super Mario Galaxy 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 Zero
Punishing GBA action with strict ranking on damage
Super Mario Galaxy 2
Precise jumps and gravity navigation define every galaxy
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Mega Man Zero
All bosses are pattern-based
Super Mario Galaxy 2
Bosses are scripted patterns, not adapting to you
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Mega Man Zero
Cyber-elf locations hidden at first
Super Mario Galaxy 2
Levels are deterministic, nothing random
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Mega Man Zero
Rank system penalises elf use, rewarding optimised clean runs
Super Mario Galaxy 2
Learning fixed layouts and routes for stars
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.