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 · Practiced Mastery
Accessible car control amid demolition chaos rather than precision racing.

Execution · Pure Mechanics
Island-themed collection of twelve motion-controlled sports showcasing the Wii MotionPlus accessory.
Dirt Showdown leans Execution (Practiced Mastery); Wii Sports Resort 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 Showdown
Drifting, boosting and ramming need solid car control
Wii Sports Resort
MotionPlus precision in swordplay, archery and bowling
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Dirt Showdown
Demolition modes reward predicting human movement a little
Wii Sports Resort
Local versus duels involve mild feinting
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Dirt Showdown
Crash physics and pack chaos add randomness
Wii Sports Resort
Slight physics and CPU pattern randomness
Dirt Showdown leans a little harder on optimization, though the gap is small.
Dirt Showdown
Event types and boost routes are quickly learnable
Wii Sports Resort
Each event has small learnable technique optima
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.