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
Classic platforming testing precise execution and the solvable boss-weakness order.

Execution · Practiced Mastery
Open-world reboot of Mirror's Edge centered on free-running across the city of Glass.
Mega Man 4 leans Execution (Practiced Mastery); Mirror's Edge Catalyst 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 4
Precise jumps and buster timing through gauntlet stages
Mirror's Edge Catalyst
Flow-state parkour with timing-based combat
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Mega Man 4
Robot Masters cycle fixed memorisable patterns
Mirror's Edge Catalyst
Enemies are scripted obstacles
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Mega Man 4
Nothing random once stages are learned
Mirror's Edge Catalyst
Open world is static once explored
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Mega Man 4
Weapon-weakness ordering and stage routing are the meta-puzzle
Mirror's Edge Catalyst
Time trials reward optimal route discovery
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.