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 · Pure Mechanics
A gothic kart racer testing drift execution and track knowledge with item chaos.

Execution · Pure Mechanics
An action racer where players detonate the environment itself to wreck rivals and reroute the track.
Nightmare Kart leans Execution (Pure Mechanics); Split/Second leans Execution (Pure Mechanics).
Split/Second leans a little harder on execution, though the gap is small.
Nightmare Kart
Drift lines and combat aim decide races
Split/Second
Drafting, drifting and dodging collapsing set pieces.
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Nightmare Kart
Human racers in versus add mild prediction
Split/Second
Timing powerplays against human rivals rewards prediction.
Split/Second leans a little harder on variance, though the gap is small.
Nightmare Kart
Item pickups inject kart-racer chaos
Split/Second
Triggered explosions and route changes upend races constantly.
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Nightmare Kart
Track knowledge and boss patterns are learnable
Split/Second
Knowing every trap and shortcut converges with play.
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.