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
Party-sized motion-timing contests with learnable per-event techniques.
Dirt Showdown leans Execution (Practiced Mastery); Mario & Sonic at the Olympic Winter Games 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
Mario & Sonic at the Olympic Winter Games
Motion-timing and button precision decide every event
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
Mario & Sonic at the Olympic Winter Games
Local human rivals add mild prediction in head-to-head events
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
Mario & Sonic at the Olympic Winter Games
Events are fixed; minor physics wobble
Dirt Showdown leans a little harder on optimization, though the gap is small.
Dirt Showdown
Event types and boost routes are quickly learnable
Mario & Sonic at the Olympic Winter Games
Each event has a learnable optimal technique
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.