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
Chaotic vehicular destruction testing driving control and map knowledge.

Execution · Practiced Mastery
A kart racer with an adventure structure and three vehicle types, lighter on item chaos than its rivals.
Carmageddon: Max Damage leans Execution (Practiced Mastery); Diddy Kong Racing leans Execution (Practiced Mastery).
Diddy Kong Racing leans a little harder on execution, though the gap is small.
Carmageddon: Max Damage
Vehicular mayhem rewards precise ramming and recovery driving
Diddy Kong Racing
Drift boosts across car, hovercraft and plane demand precision.
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Carmageddon: Max Damage
AI rivals follow routines, not your mind
Diddy Kong Racing
Multiplayer item duels add mild prediction; AI is scripted.
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Carmageddon: Max Damage
Physics chaos and pickup spawns scramble outcomes
Diddy Kong Racing
Balloon pickups and items inject moderate randomness.
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Carmageddon: Max Damage
Knowing maps, shortcuts and wreck-economy wins events
Diddy Kong Racing
Vehicle choice, balloon upgrade routes and boss strategies converge.
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.