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 · Twitch Chaos
Kart racing execution moderated by item randomness and learnable track routes.
Nightmare Kart leans Execution (Pure Mechanics); Sonic & All-Stars Racing Transformed leans Execution (Twitch Chaos).
Nightmare Kart leans a little harder on execution, though the gap is small.
Nightmare Kart
Drift lines and combat aim decide races
Sonic & All-Stars Racing Transformed
Drift timing and transforming vehicle control reward practice
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
Sonic & All-Stars Racing Transformed
Human racers add light positional mind games
Sonic & All-Stars Racing Transformed leans a little harder on variance, though the gap is small.
Nightmare Kart
Item pickups inject kart-racer chaos
Sonic & All-Stars Racing Transformed
Item rolls regularly upend race positions
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
Sonic & All-Stars Racing Transformed
Track shortcuts and drift-boost routes are learnable
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.