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
Precise rally car control over stages that reward memorisation and tuning.

Execution · Practiced Mastery
Arthur's infamous SNES gauntlet of armor-shattering hazards that must be beaten twice with the right weapon.
Dirt 3 leans Execution (Practiced Mastery); Super Ghouls 'n Ghosts 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.
Dirt 3
Car control on loose surfaces is a high physical ceiling
Super Ghouls 'n Ghosts
Committed double jump and relentless hazards punish errors
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Dirt 3
Racing the clock or scripted AI, nobody adapts
Super Ghouls 'n Ghosts
Scripted spawns, no adaptation
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Dirt 3
Surface conditions and minor physics noise per run
Super Ghouls 'n Ghosts
Chest contents and zombie spawns add light randomness
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Dirt 3
Stage knowledge and setup tuning reward study
Super Ghouls 'n Ghosts
Weapon management and mandatory second loop demand routing
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.