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
High-speed cyborg slasher built on precise parries and slicing anything in half.
Mega Man Zero leans Execution (Practiced Mastery); Metal Gear Rising: Revengeance 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
Metal Gear Rising: Revengeance
parry timing and blade-mode cuts demand sharp reactions
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
Metal Gear Rising: Revengeance
bosses telegraph fixed patterns
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
Metal Gear Rising: Revengeance
deterministic encounters
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
Metal Gear Rising: Revengeance
learning movesets and upgrade priorities
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.