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
Arcade racing with Mario Kart-style power-ups bolted onto licensed cars.

Execution · Twitch Chaos
N64 couch classic where blue shells and shortcuts decide friendships.
Blur leans Execution (Pure Mechanics); Mario Kart 64 leans Execution (Twitch Chaos).
Blur leans a little harder on execution, though the gap is small.
Blur
Racing lines and dodging shots demand car control
Mario Kart 64
Mini-turbo snaking and shortcut execution
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Blur
Human racers bait and time power-ups against you
Mario Kart 64
Couch rivals bait shells and fakes
Mario Kart 64 leans a little harder on variance, though the gap is small.
Blur
Power-up pickups and incoming attacks add chaos
Mario Kart 64
Item draws swing every race
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Blur
Track knowledge and pickup routes are learnable
Mario Kart 64
Shortcut and line knowledge is fully mapped
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.