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

Execution · Pure Mechanics
A rally racer where mastering precise car control against tricky terrain is everything.

Execution · Pure Mechanics
A rally sim testing relentless car control plus stage memorisation and setup.
Colin McRae: Dirt 2 leans Execution (Pure Mechanics); WRC 10 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.
Colin McRae: Dirt 2
precise rally driving and braking required
WRC 10
Rally car control on loose surfaces is relentless precision
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Colin McRae: Dirt 2
no adaptive opponents, mostly time trials
WRC 10
Racing the clock, not a mind
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Colin McRae: Dirt 2
weather and surface conditions vary
WRC 10
Weather and surface conditions add modest unpredictability
WRC 10 leans a little harder on optimization, though the gap is small.
Colin McRae: Dirt 2
car tuning and racing lines solvable
WRC 10
Setup tuning and memorising stage notes reward study
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.