head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is variance, and it is a single point.

Execution · Twitch Chaos
N64 couch classic where blue shells and shortcuts decide friendships.

Execution · Practiced Mastery
A kart racer testing driving precision and item management on user-created tracks.
Mario Kart 64 leans Execution (Twitch Chaos); ModNation Racers: Road Trip leans Execution (Practiced Mastery).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Mario Kart 64
Mini-turbo snaking and shortcut execution
ModNation Racers: Road Trip
Drifting and boosting at speed demands driving precision
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Mario Kart 64
Couch rivals bait shells and fakes
ModNation Racers: Road Trip
Versus humans, anticipating weapon use matters somewhat
Mario Kart 64 leans a little harder on variance, though the gap is small.
Mario Kart 64
Item draws swing every race
ModNation Racers: Road Trip
Item pickups and weapon spread add kart-racer chaos
ModNation Racers: Road Trip leans a little harder on optimization, though the gap is small.
Mario Kart 64
Shortcut and line knowledge is fully mapped
ModNation Racers: Road Trip
Track lines, boost management and shortcuts reward planning
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.