head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is execution, and it is a single point.

Execution · Practiced Mastery
Precise rally car control over stages that reward memorisation and tuning.

Execution · Pure Mechanics
A bullet-hell shmup testing reflex dodging of scripted enemy patterns.
Dirt 3 leans Execution (Practiced Mastery); Raiden IV OverKill leans Execution (Pure Mechanics).
Raiden IV OverKill leans a little harder on execution, though the gap is small.
Dirt 3
Car control on loose surfaces is a high physical ceiling
Raiden IV OverKill
Dodging dense bullet patterns demands precise reflexes
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
Raiden IV OverKill
Enemies fire fixed scripted patterns, not adapting
Raiden IV OverKill leans a little harder on variance, though the gap is small.
Dirt 3
Surface conditions and minor physics noise per run
Raiden IV OverKill
Some spawn and item randomness, mostly mappable
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
Raiden IV OverKill
Memorizing patterns and scoring routes maximizes runs
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.