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
A modern arcade flight game of high-speed dogfights, drones, and dramatic canyon runs.

Execution · Practiced Mastery
Cornering execution over memorisable circuits, with light prediction in wheel-to-wheel multiplayer.
Ace Combat 7: Skies Unknown leans Execution (Practiced Mastery); Grid 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.
Ace Combat 7: Skies Unknown
Tight dogfighting and missile-dodge timing
Grid 2
Car control through corners is the entire moment-to-moment test
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Ace Combat 7: Skies Unknown
Campaign AI scripted; small PvP scene adds little
Grid 2
Online wheel-to-wheel adds light positional prediction
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Ace Combat 7: Skies Unknown
Cloud cover gimmicks are learnable
Grid 2
Tracks are fixed and fully visible
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Ace Combat 7: Skies Unknown
Aircraft tree and loadout routing matter
Grid 2
Racing lines, braking points and car selection are studyable
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.