head to head
Neither is harder. They score identically on all four axes, so the difference between them is in kind, not degree.

Execution · Pure Mechanics
Punishing rally car control at the limit, supported by setup and stage knowledge.

Execution · Pure Mechanics
Arcade run-and-gun whose one-credit clears demand total spawn memorization and twitch.
Dirt Rally leans Execution (Pure Mechanics); Metal Slug 3 leans Execution (Pure Mechanics).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Dirt Rally
Unforgiving car control on loose surfaces is the entire test
Metal Slug 3
one-hit deaths demand frame-level dodging and aim
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Dirt Rally
Solo time trials against the clock, no adaptive rival
Metal Slug 3
every enemy wave is scripted
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Dirt Rally
Weather and surface degradation vary between stages
Metal Slug 3
branching paths vary runs slightly
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Dirt Rally
Pacenote interpretation, setup tuning and stage memorisation
Metal Slug 3
memorizing spawns is the path to a one-credit clear
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.